Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · cond-mat/0006213

Thermal Equation of State of Tantalum

Ronald E. Cohen·O. Gulseren
View original source ↗Read source document ↗Export metadata ↓

Abstract

We have investigated the thermal equation of state of tantalum from first principles using the Linearized Augmented Plane Wave (LAPW) and pseudopotential methods for pressures up to 300 GPa and temperatures up to 10000 K. The equation of state at zero temperature was computed using LAPW. For finite temperatures, mixed basis pseudopotential computations were performed for 54 atom supercells. The vibrational contributions were obtained by computing the partition function using the particle in a cell model, and the the finite temperature electronic free energy was obtained from the LAPW band structures. We discuss the behavior of thermal equation of state parameters such as the Grüneisen parameter $γ$, $q$, the thermal expansivity $α$, the Anderson-Grüneisen parameter $δ_T$ as functions of pressure and temperature. The calculated Hugoniot shows excellent agreement with shock-wave experiments. An electronic topological transition was found at approximately 200 GPa.

Explore related subjects

cond-mat.mtrl-sci

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Ronald E. Cohen, O. Gulseren. 2000-10-23. Thermal Equation of State of Tantalum. https://doi.org/10.1103/physrevb.63.224101

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Dynamic Peach-Koehler self-force, inertia, and radiation damping of a regularized dislocation

The elastodynamic Peach-Koehler force is computed for a fully-regularized straight dislocation with isotropic core in continuum isotropic elastic elasticity, in compact forms involving partial mass or impulsion functions relative to shear and compressional waves. The force accounts for both dynamic radiation damping and inertia. The expressions are valid indifferently for subsonic or supersonic velocities. Results are compared with the case of a flat-core dislocation of the Peierls-Eshelby type, for a motion of jump from rest to constant velocity. In the steady-state limit, the Lagrangian function relevant to expressing the force in the flat-core case must be replaced by a related but different function for the regularized dislocation. However, by suitably defining the regularizing dislocation width, the steady-state limits of the force for the fully-regularized and flat-core dislocations can be matched exactly.

cond-mat.mtrl-sci↗
arXiv2026

LightPFP: A Lightweight Route to Ab Initio Accuracy at Scale

Machine learning interatomic potentials (MLIPs) bridge the gap between quantum-mechanical accuracy and scalable molecular simulations. However, a fundamental trade-off persists: universal MLIPs (u-MLIPs) offer broad transferability but are computationally expensive, whereas task-specific MLIPs (ts-MLIPs) achieve high efficiency at the expense of costly DFT training data. Here we introduce LightPFP, a data-efficient knowledge distillation framework. Instead of relying on expensive DFT calculations, LightPFP constructs a distilled ts-MLIP by using a u-MLIP to generate high-quality, material-specific training data, while employing a pre-trained lightweight model to further improve data efficiency. Across diverse material systems, LightPFP reduces model development time by approximately three orders of magnitude compared with DFT-based workflows, while maintaining DFT-level accuracy. Combined with a LAMMPS/Kokkos inference backend, LightPFP achieves more than three orders of magnitude higher inference efficiency than u-MLIP baselines while enabling simulations of systems thousands of times larger. When the teacher exhibits systematic bias, LightPFP supports few-shot precision correction using as few as 10 high-accuracy DFT configurations, as demonstrated by reproducing MgO's experimental melting point. This u-MLIP-driven distillation establishes a scalable route to high-fidelity, data-efficient MLIPs, accelerating the pace of materials discovery and design.

cond-mat.mtrl-sci↗
arXiv2026

First-order polarization process as an alternative to antiferroelectricity

Antiferroelectrics generate significant interest since their polarization versus electric field (P-E) curves show typical double-hysteresis loops appealing for various applications. Unfortunately, antiferroelectrics are rare. In magnetic compounds, magnetization versus magnetic field (M-H) curves can show analogous double hysteresis loops not only in antiferromagnets but also in systems exhibiting field-induced first-order reorientation of the magnetization through a so-called first-order magnetization process. Here, we show that appealing double-hysteresis P-E loops can also appear from an unprecedented first-order polarization process. Focusing on non-polar CaTiO3, which can be turned ferroelectric under tensile strain, we study epitaxial thin films on differently-oriented NdGaO3 substrates using a combination of theoretical and experimental techniques. We uncover that a certain configuration exhibits double-hysteresis P-E loops that we rationalize from a field-induced abrupt rotation of the polarization. Such a first-order polarization process establishes a promising alternative pathway to achieve double hysteresis P-E loops appealing for practical applications.

cond-mat.mtrl-sci↗