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Journal of Physics: Condensed Matter - latest papers

Latest articles for Journal of Physics: Condensed Matter

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  • Accurate Ti–Al–Nb ternary interatomic potential development using deep neural networks for TiAl PST single crystals
    A deep learning-driven Ti–Al–Nb ternary interatomic potential is developed continuously through DP-GEN framework, combining first-principles accuracy with molecular dynamics scalability. The neural network potential demonstrates exceptional transferability in predicting critical properties of Nb-doped γ-TiAl and α2-Ti3Al phases. Nb influence on shear deformation in α2-Ti3Al is investigated. Meanwhile, Nb-doped α2/γ interface tensile perpendicular to the interface and shear simulations along 1/2[ ] and 1/2[ ] are performed in order to simulate the local configurations in Ti–Al PST single crystals. This model provides a computational framework for interfacial engineering in lamellar TiAl alloys.

  • Spin-exchange induced spillover on poor man’s Majoranas in minimal Kitaev chains
    The ‘poor man’s Majoranas’ (PMMs) (Leijnse and Flensberg 2012 Phys. Rev. B86 134528) devoid of topological protection can ‘spill over’ from one edge into another of the minimal Kitaev chain when perturbed electrostatically. As aftermath, this leads to a delocalized Majorana fermion (MF) at both the edges. Additionally, according to recent differential conductance measurements in a pair of superconducting and spinless quantum dots (QDs), such a PMM picture was brought to reality (Dvir et al 2023 Nature614 445; ten Haaf et al 2024 Nature630 329). Based on this scenario, we propose the spillover of the PMM when its QD is exchange coupled to a quantum spin S. We show that if this QD is perturbed by the exchange coupling J, solely the half of the fine structure stays explicit for a fermionic (bosonic) Concurrently, the other half squeezes itself as the delocalized MF zero-mode. Particularly, turning-off the superconductivity the multiplicity holds regardless the spin statistics. Meanwhile, the PMM spillover induced by J becomes a statistics dependent effect. Hence, our findings contribute to the comprehension of spin-phenomena interplay with superconductivity in minimal Kitaev chains, offering insights for future quantum computing devices hosting PMMs.

  • A quantitative relationship between electron localization function and the strength of physical binding
    The electron localization function (ELF) measures electron localization in matter and provides insights into bonds in materials and molecules. This study examines the relationship between ELF and binding energy in bimolecular systems, focusing on van der Waals (vdW) interactions such as Keesom, Debye, and London dispersion forces. These interactions play significant roles in crystalline molecular materials. This work addresses the challenge of accurately calculating binding energies in molecular materials and supramolecular synthons by exploring their correlation with ELF. We use density functional theory and have evaluated seven exchange-correlation functionals to identify which functional provides the most accurate binding energies in comparison to values obtained with coupled cluster. The findings revealed that rev-vdW-DF2 offers high precision, whereas Perdew–Burke–Ernzerhof-D3(BJ) is computationally efficient. These functionals were utilized to demonstrate how ELF can be employed to accurately determine binding energies. By analyzing the ELF and its correlation with binding energies in 95 bimolecular systems held together with physical bindings ranging from weak to strong interactions, we demonstrate a strong linear correlation, with a coefficient of determination (R2) reaching 0.960. These findings suggest that ELF can effectively differentiate between weak and strong vdW interactions, providing a reliable quantitative metric for evaluating interaction strengths. The results indicate that ELF can be used as method to determine the strength of intermolecular interactions, with potential applications in materials science. Especially as a method for analyzing and predicting molecular interaction strengths within molecular materials and supramolecular synthons. This work opens up the possibility to derive all directional physical binding energies of molecular materials within the unit cell directly from the ELF, which has the potential to simplify practical calculations. Furthermore, the study revealed a possible systematic error for current xc-functionals in describing systems with two neighboring O–H⋯O hydrogen bonds between interacting molecules.

  • Magnetic, thermoelectric, and electrical transport properties of CsMn4As3
    The present investigation utilized first-principles methodologies to elucidate the electronic and magnetic characteristics of bulk CsMn4As3. Our results validate the Mott insulator behavior of this compound, which is in agreement with the existing literature. Through the application of the Heisenberg spin Hamiltonian approach and energy mapping methods, we determined the exchange interactions, highlighting potential spin frustration in the material. Verification of the mechanical and dynamical stability of CsMn4As3 was conducted, followed by an assessment of its thermoelectric attributes. The observed low lattice thermal conductivity along the c-axis of the compound significantly contributes to a substantial figure of merit (ZT) of 0.8 at 500 K. Leveraging the inherent layered architecture of the material, we modeled a monolayer device and verified its structural integrity through phonon and molecular dynamics analyses. The monolayer exhibited metallic characteristics, prompting an investigation into its I–V response, which uncovered subtle negative differential conductance phenomena. These results underscore the imperative for continued experimental validation to unlock the potential for advanced electronic applications.

  • Quantum thermoelectrics in closed circuit with non-equilibrium electrons
    The influence of a non-equilibrium classical environment on the parameters of a quantum heat converter in a closed circuit at a given (non-zero) output power is theoretically investigated. It is shown that the non-equilibrium of the electron distribution function in metal terminals contributes to the kinetic coefficients of the linear approximation. Analytical expressions of the Seebeck and Peltier coefficients are obtained, considering the non-equilibrium in the terminals when electric current and heat flow through the system. The influence of non-equilibrium on the theoretical power limit and efficiency of the heat engine at a fixed output power is also determined. Closed-form solutions were obtained for the quantum bound of the heat engine output power and the theoretical limit of the heat conversion efficiency at a given output power in quantum systems with a non-equilibrium environment for certain limited cases. A spectroscopic thermoelectric method for studying quantum systems is proposed.