Materials Science
Transferable 3D Convolutional Neural Networks for Elastic Constants Prediction in Nanoporous Metals
Sergei Zorkaltsev, Rafał Topolnicki, Tal-El Carmon et al. (+4 more)
The
topology of nanoporous metals is crucial for determining their mechanical response. In this work, we generated 6,000 gold and 422 silver nanoporous structures and calculated three components of elastic modulus with Molecular Dynamics simulations, resulting in 19,263 data points. This study compared two distinct approaches of predicting elastic modulus: a Fully-Connected neural network trained on precomputed topological descriptors, and several 3D Convolutional neural network architectures adapted from computer
vision. The 3D CNNs outperformed the descriptor-based baseline model ($R^2 = 0.704$), with to-performing DenseNet-201 architecture achieving $R^2 = 0.955$. Additionally, the effects of training grid resolution,
dataset size, and descriptor integration into a model were investigated. We further demonstrated model robustness through Transfer learning: a pretrained model was fine-tuned on a much smaller
dataset of denser gold structures and the
dataset of denser silver structures. Finally, the trained model was employed to evaluate the mechanical properties of 100,000
stochastic nanoporous gold structures and identify the Pareto optimal designs.
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All authors Sergei Zorkaltsev, Rafał Topolnicki, Tal-El Carmon, Santhosh Mathesan, Paweł Dłotko, Dan Mordehai, Maciej Harańczyk
Soft Condensed Matter
Monte Carlo simulation of selective adsorption in a binary hard-disk mixture on patterned adhesive surfaces
N. Kukarkin and T. Patsahan
Selective adsorption in a two-dimensional model of a binary hard-disk mixture on patterned adhesive surfaces is studied using grand canonical Monte Carlo simulations. The two species have equal diameters and equal bulk chemical potentials, but different attraction strengths to adhesive domains. Thus, affinity-driven selectivity is separated from particle-size asymmetry and unequal chemical potentials. The surface pattern is defined by domain size, domain surface coverage, and ordered or disordered arrangement of circular domains. The results show that selectivity strongly depends on surface geometry, especially at low and intermediate chemical potentials. Domains comparable to the particle size enhance selectivity by forming adsorption regions with large particle–domain overlap, whereas larger domains can provide high selectivity at low chemical potentials. For small domains, further reduction in size can also increase selectivity as the system approaches a uniform attractive surface with corresponding effective affinity parameters of the species.
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Mesoscale and Nanoscale Physics
The Topography Trap: Sifting Interlayer Excitons from Strain-Related Artifacts in Real-World 2D Hetrostructures
Pablo Hernández López, Luka Pirker, Astrid Weston et al. (+8 more)
Novel excitonic phenomena emerging in transition metal dichalcogenide (TMDC)
heterostructures belong to the most exciting topics in contemporary physics of van der Waals materials. Interlayer
excitons (IXs) stand out among those due to their long radiative lifetimes and tunability by electric fields, strain, and twist angle. However, many ambiguities persist in the optical identification and manipulation of IXs, highlighting the need for reliable spectroscopic criteria that distinguish interlayer species from spurious signals. Here, we present a decision-tree protocol that evaluates interlayer coupling via intralayer
exciton quenching and correlates photoluminescence (PL) with atomic force microscopy (AFM) to correctly assign room-temperature PL features in TMDC-based
heterostructures. Applying this protocol, we identify momentum-direct IX between the K valleys of the two layers (KK-IX) in MoS2-MoSe2 and MoS2-WSe2
heterostructures at room temperature. In contrast, our protocol contests the reported bright, momentum-indirect, twist-angle-independent $\Gamma$K-IX in MoS2-WSe2. Comprehensive experimental data, including infrared and tip-enhanced photoluminescence (TEPL) with sub-diffraction-limited resolution, show no compelling evidence for this excitonic species, despite numerous reports. Instead, the spectroscopic features previously assigned to this $\Gamma$K-IX originate from locally strained WSe2 at topographical inhomogeneities of the
heterostructure interface, underscoring the need for robust, spatially resolved characterization of real-world samples in this highly accessible field and providing a generally applicable framework for identifying interlayer
excitons in 2D
semiconductor heterostructures.
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All authors Pablo Hernández López, Luka Pirker, Astrid Weston, Arijit Kayal, Rafael Nadas, Adrián Dewambrechies Fernández, Álvaro Rodríguez, Roman Gorbachev, Kirill I. Bolotin, Otakar Frank, Sebastian Heeg
Soft Condensed Matter
Unifying Plasticity in Ordered and Disordered Matter using Topological and Geometrical Descriptors
Xin Wang, Yang Xu, Jin Shang et al. (+5 more)
Identifying the regions responsible for plastic flow in amorphous solids remains an open problem, since structural disorder seems to prevent the direct application of concepts such as dislocations, topological defects that successfully describe irreversible deformations in crystalline systems. Here, we introduce fields of dislocation, disclination, and incompatibility densities, that in
crystals reduce to the standard sources of plasticity and assess their predictive power in amorphous materials. We find that, in a simulated two-dimensional glass as well in two- and three-dimensional experimental granular systems, these fields exhibit strong spatial correlations with $D^2_{\text{min}}$, a standard descriptor used to locate plastic events in disordered solids under shear, indicating that these fields are indeed reliable quantities for predicting plastic events. In contrast to $D^2_{\rm min}$, these fields provide deeper insight into how local rotational and translational motions become coupled well before the onset of plastic events. Moreover, by allowing the two contributions to be disentangled, they reveal that rotational defects become increasingly dominant in three dimensions. Our approach paves the way for describing plasticity in crystalline and amorphous solids in a unified manner.
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All authors Xin Wang, Yang Xu, Jin Shang, Yi Xing, Jie Zhang, Yujie Wang, Walter Kob, Matteo Baggioli
Mesoscale and Nanoscale Physics · Cross-listed from physics.app-ph
Lasing from SOI-integrated GaAsSb nanowires via resonator-driven optical feedback
J. Zöllner, C. Doganlar, C. García Marcilla et al. (+3 more)
Silicon photonic integrated
circuits critically depend on compact on-chip light sources, for which nanowire (NW)
lasers are an attractive solution. However, their practical implementation is often limited by broad emission linewidths and poor frequency stability resulting from weak optical feedback. Here, we integrate individual GaAsSb NWs by transfer-printing onto silicon-on-
insulator (SOI) racetrack resonators to realize optical feedback at silicon-transparent wavelengths. Finite-difference-time-domain simulations reveal efficient coupling between the hybrid NW-waveguide mode and the fundamental TE resonator mode, with calculated cavity Q-factors exceeding 10$^4$. Experimentally, we observe feedback-induced lasing emission at a low threshold (P$_{th}$) of 8.6 $\pm$ 1.8 $\mu$J/cm$^2$. Compared to identical NW
lasers without SOI resonator, the linewidth is reduced by more than a factor of four at 3P$_{th}$ and remains stable below 1.8 meV up to 5P$_{th}$. Our results demonstrate NW-based light sources on SOI and show that tailored resonator designs enable improved linewidth control and frequency stabilization.
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All authors J. Zöllner, C. Doganlar, C. García Marcilla, S. Meder, G. Koblmüller, J. J. Finley
Materials Science · Cross-listed from math.OC
Polynomial diagrams for microstructure modelling
David P. Bourne, Maciej Buze, Thomas Gallouët et al. (+1 more)
We formulate a framework of
polynomial diagrams, which are a generalisation of power diagrams (PDs) and anisotropic power diagrams (APDs) allowing for boundaries between
cells to be algebraic curves of a prescribed degree. We show that they arise naturally from rephrasing PDs (APDs) as first-degree (second-degree) instances of linear parametrised minimisation diagrams. We also develop an efficient GPU-accelerated framework for fitting
polynomial diagrams to image data using Legendre
polynomials and by maximising a regularised concave objective function adapted from classical logistic regression literature. A largely self-contained analysis of the optimisation
algorithm is also provided, including identification of scale and gauge invariances and the limiting objective function as the regularisation parameter vanishes. We apply the
algorithm to fit
polynomial diagrams to electron backscatter diffraction images of steel.
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All authors David P. Bourne, Maciej Buze, Thomas Gallouët, Quentin Mérigot
Mesoscale and Nanoscale Physics
Field-tunable spin-valley transport in monolayer MoS$_2$
Kamal Azaidaoui, Hocine Bahlouli, Clarence Cortes et al. (+2 more)
We study field-controlled
spin-valley transport in monolayer MoS$_2$ through a single electrostatic barrier and a uniform off-resonant elliptically polarized irradiation. Starting from the massive Dirac
Hamiltonian with intrinsic
spin-orbit coupling, we use a high-frequency Floquet expansion to obtain an effective static model with a
laser-renormalized mass (gap) term. We solve the scattering problem by spinor matching and derive the exact analytic expression for the transmission. The numerical results show that the drive tunes both the
spin-valley-dependent propagation threshold inside the barrier and the Fabry-Pérot phase, creating controllable pass/stop bands. By varying both the
laser intensity (amplitude) and the polarization shape, we show that the same junction can be switched between broadband valley filtering and resonance-selective operation, and the valley contrast remains visible in the Landauer conductance. Our findings establish an efficient route for realizing optically reconfigurable valleytronic and spintronic functionalities in MoS$_2$.
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All authors Kamal Azaidaoui, Hocine Bahlouli, Clarence Cortes, David Laroze, Ahmed Jellal
Materials Science
Anisotropic Crystallization Kinetics and Interfacial Dynamics of Phase-Change Material Sb$_2$S$_3$ from Machine Learning Force Field Simulations
Souvik Chakraborty, Wen-Qing Li and Yun Liu
The phase-change material antimony sulfide (Sb$_2$S$_3$) relies on rapid and reversible phase transitions between crystalline and amorphous states, which are critical for their performance in data storage and photonics applications. In this work, a machine learning force field is developed based on the moment tensor potential approach, allowing us to understand the atomistic origin of the structural
evolution and crystallization kinetics in Sb$_2$S$_3$ for the first time, by enabling large-scale molecular dynamics simulations (up to 7680 atoms for 40 ns). Sb$_2$S$_3$ shows anisotropic growth rates with the [100] facet exhibiting the fastest growth due to the strong Sb-S covalent bonding along its quasi-1D ribbon-like structure of its crystalline phase. The activation energy for
crystal growth is found to be 0.55-0.57 eV, whereas that for
diffusion is around 1.16-1.56 eV. The lower activation energy for
crystal growth indicates that its heterogeneous crystallization is interface controlled rather than
diffusion limited, unlike GST and GeTe with atomic attachment at the solid-
liquid interface being energetically favoured over long range atomic transport. These findings provide key insights into the structural, thermodynamic, and kinetic properties of Sb$_2$S$_3$, paving the way for optimizing its functionality including switching speed, reliability, and energy efficiency.
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Materials Science
Generalized Phase Diagrams for Graphene CVD growth on Copper
Tongtong Wang, Ke Jin, Yishi Zhang et al. (+1 more)
Understanding the competition between first-layer lateral expansion and second-layer nucleation is essential for layer-controlled
graphene growth via chemical vapor deposition (CVD). Building on our previous phase diagram framework based on the dimensionless parameters $\alpha$ and $\Gamma$, we develop an enhanced model incorporating two previously neglected effects: thermal-expansion-induced substrate strain and chemical desorption of carbon monomers via reverse dehydrogenation. First-principles calculations are employed to determine the strain-dependent
diffusion and attachment barriers on both exposed and
graphene-covered Cu(111) surfaces. By mapping the multi-step CVD process into an effective quasi-physical vapor deposition, we construct a generalized phase diagram characterized by the coupled effects of $\alpha$, $\Gamma$, and a newly introduced desorption parameter $Z$. Our results show that tensile strain expands the
bilayer graphene (BLG) growth window for critical
nucleus sizes $i^*>1$. In contrast, chemical desorption suppresses BLG formation in the high-$\Gamma$ regime via $Z$-dependent monomer depletion. This unified framework provides a predictive guide for the rational synthesis of high-quality
bilayer graphene by linking macroscopic growth parameters to microscopic layer-selection mechanisms.
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All authors Tongtong Wang, Ke Jin, Yishi Zhang, Dajun Shu
Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
Cameron Jones, Jonathan Y. Huang, Santiago Serrano et al. (+13 more)
Spin qubits in silicon-MOS (SiMOS)
quantum dots have recently demonstrated compatibility with existing industry standard CMOS fabrication techniques. These devices have routinely achieved single- and two-
qubit gate fidelities above 99% and demonstrated highly entangled two-
qubit Bell states in isolated double
quantum dot (DQD) unit
cells, however coupling between unit
cells has remained challenging. In this work, we present a two unit
cell, four-
qubit SiMOS processor with universal controllability and fully parallelised state initialisation and readout. We use this processor to generate maximally entangled three-
qubit states, including the Greenberger-Horne-Zeilinger (GHZ) state, and certify multipartite
entanglement through violation of the classical Mermin-witness bound. By using a fully symmetric dynamically decoupled gate sequence to create our entangled states, we are able to preserve the lifetime of the
entanglement beyond $T_2^*$, to a time limited instead by $T_2^\textrm{Hahn}$. These demonstrations pave a road to the scalable operation of larger SiMOS processors, and achieving high purity, long-lived multi-
qubit entangled states in them.
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All authors Cameron Jones, Jonathan Y. Huang, Santiago Serrano, MengKe Feng, Gerardo A. Paz-Silva, Tuomo Tanttu, Paul Steinacker, Fay E. Hudson, Wee Han Lim, Nikolay V. Abrosimov, Hans-Joachim Pohl, Michael L. W. Thewalt, Andrew S. Dzurak, Andre Saraiva, Arne Laucht, Chih Hwan Yang
Soft Condensed Matter
What Lies Between Crystal and Randomly Packed Structures? A General Characterization of Non-Periodic Order
Ian Douglass and Peter Harrowell
In this paper we address the characterization of the structure of condensed materials, periodic and non-periodic. Carrying out an extensive study of over 7000 different groundstate structures of a 2D
lattice model of binary packing, we find a predominance of non-periodic structures (over 96%) that extend across the entire range of possible diversities. These non-periodic structures are resolved by establishing whether a structure will accommodate or reject additional local structures. This property, structural selectivity, is treated as a signature of an underlying ordering principle. The major result of the paper is the determination that roughly 35% of the non-periodic structures are selective and, hence, ordered in some way. This selectivity extends up to a diversity of ~ 9, well beyond the upper threshold for diversity in periodically ordered states.
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Strongly Correlated Electrons
Giant nonlinear conductivity in 2D electron gas from substrate-induced dipolar scattering
Dmitry V. Chichinadze, Alexander Seidel and Zohar Nussinov
Despite a surge of interest in the nonlinear transport in 2D materials, a fundamental puzzle remains: existing theoretical frameworks are unable to quantitatively account for the
giant nonlinear conductivities ($\gtrsim 1 \frac{\mu \text{m}}{\Omega \text{V}}$) recently reported in 2D van der Waals
heterostructures. Here, we introduce a mechanism based on electron scattering from a substrate-induced dipole array linked to short-range
impurities. We show that the strict kinematic constraints, inherent to 2D scattering, lead to a singular enhancement of the nonlinear response, fundamentally dictating a natural scale of $1 \frac{\mu \text{m}}{\Omega \text{V}}$.
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Superconductivity
Carrier-doping effect and anomalous transport properties in Ni-doped CeCoIn5 investigated by Hall resistivity measurements
Ryosuke Koizumi, Hayao Fujimoto, Teppei Takahashi et al. (+10 more)
We investigated the effects of Ni doping on carrier density and anomalous electrical transport properties in CeCo$_{1-x}$Ni$_x$In$_5$ ($x \leq 0.3$) by performing
Hall resistivity measurements. The carrier density, estimated from the
Hall coefficient $R_{\rm H}$ at a temperature of 0.5 K in high
magnetic fields, increases linearly with $x$, indicating that the doped Ni ions act as electron dopants. In CeCoIn$_5$, the magnitude of $-R_{\rm H}$ is strongly enhanced at
magnetic fields near the superconducting upper critical field $H_{c2}$ and in the low-field region above the superconducting transition temperature $T_c$. However, these anomalies are found to be significantly suppressed by Ni doping. Possible origins of this suppression in $-R_{\rm H}$ are discussed.
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All authors Ryosuke Koizumi, Hayao Fujimoto, Teppei Takahashi, Azumi Yashiro, Haruna Kawakami, Kazuki Ishii, Hinako Kosaka, Takeshi Hasegawa, Yusei Shimizu, Ai Nakamura, Dai Aoki, Kenichi Tenya, Makoto Yokoyama
Strongly Correlated Electrons
Strain-Tuned Incommensurate Kekulé Spiral Order in Twisted Bilayer Graphene: A Quantum Many-Body Study
Cheng Huang, Yves H. Kwan, Maksim Ulybyshev et al. (+3 more)
The physics of twisted
bilayer graphene away from the exactly solvable
chiral limit and the
quantum Monte Carlo sign-problem-free charge neutrality point is elusive due to the exponential increase in the computational complexity, which has rendered explanations of experimentally observed insulating and superconducting phases restricted largely to the perturbative level. Here we focus on the filling factor $\nu=\pm2$ and address the question of the strain dependence of the interacting ground state by approximate
quantum Monte Carlo (AQMC), state-of-the-art exact diagonalization (ED) and Hartree-Fock (HF) mean field, in order to investigate the strain-tuned transition from the Kramers intervalley coherent (KIVC) state to the incommensurate Kekulé spiral (IKS) state. While all three methods capture the KIVC order, only ED and HF detect the weaker IKS order that AQMC does not capture adequately. As the AQMC is still capable of capturing stronger orders like the KIVC, our combined protocol may open the door for further understanding of the rich phases of twisted
bilayer graphene and other strongly-correlated systems.
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All authors Cheng Huang, Yves H. Kwan, Maksim Ulybyshev, Fakher F. Assaad, Laura Classen, Zi Yang Meng
Materials Science
Tuning the low-energy band structure in twisted bilayer WSe2
T.-H.-Y. Vu, O. J. Clark, N. H. Jo et al. (+21 more)
Tuning the electronic structures of two-dimensional (2D) material-based
heterostructures is of crucial importance for their use in functional next-generation electronics. Here, through angle-resolved photoemission spectroscopy with nanoscale spatial resolution (nano-ARPES), we systematically track the
evolution of the near-
Fermi-level electronic structure of
bilayer WSe2 over a large range of twist angle. While the momentum positioning of the valence band maxima is independent of twist angle, we find that the energetic separation between the hole bands at the K point of the Brillouin zone and the higher binding-energy hole band at {\Gamma} can be varied in excess of 100 meV. We explore the mechanisms underpinning this
evolution and discuss the implications for tuning both the size of the band gaps, and the efficiency of the
spin-dependent electron-
phonon coupling channels in homobilayer transition metal dichalcogenide devices.
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All authors T.-H.-Y. Vu, O. J. Clark, N. H. Jo, J. Blyth, Q. Li, C. Jozwiak, A. Bostwick, J. B. Muir, L. Jia, J. A. Davis, I. Di Bernardo, A. Grubisic Cabo, K. Xing, W. Zhao, S. H. Ryu, S. H. Lee, Z. Mao, K. Watanabe, T. Taniguchi, B. A. Chambers, S. L. Harmer, E. Rotenberg, M. S. Fuhrer, M. T. Edmonds
Strongly Correlated Electrons · Cross-listed from quant-ph
Entangling Power: A Probe of Symmetry and Integrability in Quantum Many-Body Systems
Ian Low and Pallab Goswami
The entangling power of a
unitary operator quantifies its ability to generate
entanglement from product states and provides a natural probe of
quantum many-body dynamics.
Entanglement extremization at points of enhanced
symmetry has previously been observed in high-energy scattering. In this work we compute the time-averaged entangling power of anisotropic Heisenberg
spin chains across two-site models and finite-size systems, as well as the entangling power of the two-
magnon $S$-
matrix in the thermodynamic limit. For two-site models we establish a monotonic hierarchy: the entangling power decreases as the
symmetry group grows, reaching its minimum at the $SU(2)$ XXX point. Finite-size XXZ chains exhibit sharp dips at the $SU(2)$ points $\Delta=\pm 1$ and the free-
fermion point $\Delta=0$, with the free-
fermion dip decaying much more slowly with system size. In the thermodynamic limit, we decompose the two-
magnon $S$-
matrix into
quantum logic gates – Identity, SWAP, and $\sigma_z\otimes\sigma_z$ – and show that the entangling power vanishes for all scattering energies at the $SU(2)$ points, where the $S$-
matrix reduces to the Identity gate, while the free-
fermion point achieves the maximum – the opposite of the finite-size many-body behavior. The entangling power can serve as an operator diagnostic for
symmetry and selected aspects of integrability in
quantum simulations of
spin-chain dynamics.
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Disordered Systems and Neural Networks · Cross-listed from quant-ph
Entanglement Growth from Structured Initial States in Many-Body Localized Systems
Chen Xu and Pengfei Zhang
Understanding how complex
entanglement structures emerge is a central problem in
quantum many-body physics. Recent work by Zhang et al. [Phys. Rev. Lett. 137, 020404 (2026)] has considered structured initial states prepared by evolving a product state under a chaotic
Hamiltonian for a finite time before quenching to the target
Hamiltonian. In this setup, total
entanglement entropy growth in many-body localized systems exhibits two distinct regimes, first increasing and then decreasing as the initial
entanglement is tuned. In this work, we identify the physical origin of this behavior by analyzing the dynamics of both the Rényi
entanglement entropy and the Wehrl-Rényi
entropy in the random-field XXZ model, the latter of which characterizes multipartite
entanglement. We show that a similar non-monotonic dependence on the initial
entanglement also appears in the net growth of the Wehrl-Rényi
entropy for product states polarized along the $z$-direction. The first regime is governed by a finite magnetization associated with local integrals of motion, while the second reflects inter-site correlations. In contrast, for product states in the $x/y$-direction, the
entanglement growth exhibits a monotonic decay. Our results provide a more fine-grained picture of how distinct initial-state properties shape
entanglement dynamics in many-body localized systems.
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Materials Science
Interacting donor-acceptor pairs as the origin of coupled spin-optical signals in hexagonal boron nitride
Guanjian Hu, Jijun Huang, Bing Huang et al. (+1 more)
Optically addressable
spin defects in hexagonal boron nitride hold promise for room-temperature
quantum technologies, but their microscopic identities remain largely unknown. Using first principles calculations, we show that coupled
spin optical signals arise from interacting donor acceptor pairs, not the commonly believed isolated defects. Intra and inter pair separations control charge transfer, electronic structure, and
spin coupling, thereby greatly modulating zero
phonon lines,
phonon sidebands, lifetimes, and the sign of optically detected
magnetic resonance contrast. Importantly, we identify two distinct charge-state-dependent coupling regimes and extend this picture to correlated defect ensembles, explaining the wide diversity of experimental observations. Our results establish a microscopic framework for coupled defect behavior and provide design principles for
spin-active
quantum emitters in wide bandgap
semiconductors.
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All authors Guanjian Hu, Jijun Huang, Bing Huang, Song Li
Superconductivity
Pressure-induced superconductivity in epitaxially-stabilized Pr$_3$Ni$_2$O$_7$ films
Motoki Osada, Chieko Terakura, Hsiao-Yi Chen et al. (+8 more)
The discovery of high critical-temperature $T_{\mathrm{c}}$ superconductivity in La$_3$Ni$_2$O$_7$ under high pressure has led to a rapid expansion of the $T_{\mathrm{c}}$ range through lanthanide $Ln$ substitution, and to ambient-pressure superconductivity in strained thin films, yet the exploration of new
bilayer nickelates remains strongly constrained by thermodynamic stability. Beyond the difficulty of synthesis of bulk single-
crystals, here we report on the pressure-induced high-$T_{\mathrm{c}}$ superconductivity in epitaxially-stabilized Pr$_3$Ni$_2$O$_7$ thin films. While the Pr$_3$Ni$_2$O$_7$ films exhibit insulating behaviour at ambient pressure regardless of ozone-annealing treatment, they show $T$-linear metallic transport and superconductivity reaching an onset $T_{\mathrm{c}}$ of 66 K and zero-resistance at nearly 40 K at 22 GPa. Furthermore, Nd$_3$Ni$_2$O$_7$, with the smaller rare-earth ion Nd, can also be stabilized, however, superconductivity is not observed in the measured pressure range. Epitaxial stabilization enables us to examine the dependence of $T_{\mathrm{c}}$ and the critical pressure $P_{\mathrm{c}}$ for superconductivity on the $Ln$ ion in $Ln_3$Ni$_2$O$_7$ ($Ln$ = La, Pr, Nd). These results suggest that a higher $P_{\mathrm{c}}$ is required for smaller $Ln$ ions, consistent with trends observed in bulk studies of $Ln$ substitution. This study demonstrates that epitaxial stabilization is a powerful technique to further expand the family of superconducting
bilayer nickelates.
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All authors Motoki Osada, Chieko Terakura, Hsiao-Yi Chen, Akiko Kikkawa, Masamichi Nakajima, Ryoma Asai, Jean-Baptiste Morée, Yusuke Nomura, Ryotaro Arita, Yoshinori Tokura, Atsushi Tsukazaki
Superconductivity · Cross-listed from quant-ph
WSi weak link element with a non-sinusoidal current-phase relation
Sarah Garcia Jones, Trevyn F. Q. Larson, Sai Pavan Chitta et al. (+7 more)
Nonlinearity is an essential ingredient for encoding
quantum states with non-uniform energy spacing, implementing coherent
quantum gates, reading out
qubits, amplifying, and mixing electromagnetic signals. In this work, we demonstrate the nonlinear behavior of a constriction fabricated from an amorphous, high-kinetic inductance material, tungsten silicide, embedded in a three-dimensional RF-SQUID. We find that the results are consistent with the weak link behaving as a Josephson junction with a sawtooth-like current-phase relation or a
quantum phase slip element. Finally, we measure relaxation times of the metastable, persistent-current states trapped in the local minima of the potential.
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All authors Sarah Garcia Jones, Trevyn F. Q. Larson, Sai Pavan Chitta, Heli Vora, Varun Verma, Sae Woo Nam, José Aumentado, Jens Koch, Raymond W. Simmonds, András Gyenis
Mesoscale and Nanoscale Physics · Cross-listed from physics.optics
Probing Lattice Dynamics in Real-Space and Real-Time
Navdeep Rana
The coherent
lattice vibrations significantly impact physical and chemical processes in solids, such as heat transfer, displacive phase transitions, and thermal conductivity. Thus, probing
lattice dynamics in real-space and real-time is essential for understanding ubiquitous phenomena in solids. High-harmonic spectroscopy (HHS) has emerged as a preferred technique for investigating static and dynamic properties of solids on ultrafast timescales. Yet, despite these accomplishments, the applicability of HHS to probe the influence of coherent
lattice vibrations on electronic responses has remained unexplored. In this thesis, we explore the impact of coherent
lattice dynamics on attosecond electronic responses in solids using HHS. We observe that coherent excitation of the in-plane
phonon mode in
graphene results in sidebands in the harmonic spectrum, separated by the frequency of the excited
phonon mode. Additionally, we demonstrate the capability of HHS to characterize energy, polarization, phase difference, and the "chirality" of
phonon modes. This thesis offers an avenue to probe
phonon-driven processes in solids with sub-cycle temporal resolution. In the later segment, our focus shifts toward probing coherent
lattice dynamics in real-space and real-time. We demonstrate that inelastic scattering techniques, combined with theoretical analysis, yield comparable results to those from time-resolved diffraction and imaging measurements within pump-probe configurations. Our findings exhibit excellent agreement with results from a time-resolved diffuse x-ray scattering experiment. Our proposed method serves as an alternative to time-resolved diffraction and imaging methods for probing
lattice dynamics in real-space and real-time with atomic-scale spatiotemporal resolution.
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Materials Science · Cross-listed from cs.LG
TriForces: Augmenting Atomistic GNNs for Transferable Representations
Ali Ramlaoui, Alexandre Duval, Hannah Bull et al. (+4 more)
Machine learning interatomic potentials (MLIPs) achieve excellent accuracy when trained on large Density Functional Theory (DFT) data. To be useful in practice, they must often be adapted to target chemistries using small and expensive task-specific
datasets. However, MLIPs transfer inconsistently across domains, with representations that often loose accessible composition and structure information. To address this, we present TriForces, a model-agnostic three-stream framework that separates composition and structure information, combined with self-supervised learning to preserve transferable representations. TriForces improves performance on MatBench and QM9 over baselines without needing DFT labels and enables efficient similar structure
retrieval through its learned latent space. On OMat24, in limited-data training regime, TriForces reduces energy MAE by 57% at 20K samples only and improves force MAE across sample sizes. We release pretrained TriForces variants across multiple MLIP architectures with code at https://github.com/Ramlaoui/triforces.
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All authors Ali Ramlaoui, Alexandre Duval, Hannah Bull, Victor Schmidt, Hugues Talbot, Fragkiskos D. Malliaros, Joseph Musielewicz
Materials Science
The Dislocation Content of Triple Junctions
Ian S Winter, R. Daniel Moore, R. E. Rudd et al. (+2 more)
Triple junctions, line defects formed by the intersection of different grain boundaries, exist within all polycrystalline materials. While it has long been recognized that triple junctions could play an important role in microstructural
evolution, there remains much uncertainty regarding their properties. Triple junctions are line defects capable of carrying dislocation content. However, no general method for calculating this content has been established. In this work, we derive the necessary equations to calculate the intrinsic dislocation content of a triple junction whose trichromatic pattern forms a coincidence site
lattice. We further show that this approach can be easily applied to facet junctions, and in principle, any type of grain boundary junction for which a coincidence site
lattice can be defined. We apply this formalism to atomistic simulations of tungsten to compute the Burgers vectors of a facet junction and a triple junction formed during twin grain nucleation and growth from a free surface. By tracking the
evolution of the triple junction's Burgers vector and its core structure, we reveal the sequence of individual line defect reactions responsible for triple-junction-mediated twin growth.
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All authors Ian S Winter, R. Daniel Moore, R. E. Rudd, T. Oppelstrup, T. Frolov
Strongly Correlated Electrons
Distinct lattice and charge excitations in AV3Sb5 kagome superconductors
Dongjin Oh, Stefan Enzner, Lennart Klebl et al. (+12 more)
The kagome
superconductor family AV3Sb5 (A=Cs, Rb, K) provides a rich platform for exploring diverse electronic
symmetry breaking phenomena, including superconductivity and various forms of density wave orders. Although these compounds share the identical
lattice structure in the normal state, they exhibit distinct forms of
symmetry breaking upon entering the charge density wave (CDW) phase, and the microscopic origin of which remain elusive. Here, we investigate the
lattice and charge degrees of freedom in AV3Sb5 using angle-resolved polarized Raman spectroscopy. Our comprehensive polarization-resolved measurements reveal that the lifting of the twofold-degeneracy of the E2g
phonon mode in the CDW phase-previously reported only in CsV3Sb5 with a 3 GHz splitting-also appears ubiquitously in the other two compounds. In contrast, the collective CDW excitations exhibit markedly different polarization dependences depending on the alkali-metal species. These distinct behaviors in the
lattice and charge channels provide crucial insight into the enigmatic material-dependent
symmetry breaking phenomena that appear in the CDW phase. Furthermore, our experiments, together with first-principles calculations and an effective
Hamiltonian model, shed light on the nature of the charge order structure in AV3Sb5 kagome
superconductors.
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All authors Dongjin Oh, Stefan Enzner, Lennart Klebl, Harley D. Scammell, Julian Ingham, Tim Wehling, Giorgio Sangiovanni, Ronny Thomale, Ahmet Kemal Demir, Connor Occhialini, Dirk Wulferding, Ziqiang Wang, Andrea C. Salinas, Stephen D. Wilson, Riccardo Comin