Anisotropic electrical and thermal conductivity of TiH₂ across its crystalline phase transition: A first-principles study
Abstract
Titanium dihydride (TiH₂) undergoes a reversible phase transition from a face-centered tetragonal (fct) to a face-centered cubic (fcc) structure near 310 K, driven by temperature-dependent changes in its c/a lattice parameter ratio. Using first-principles density functional theory (DFT) and Boltzmann transport theory, we investigate the anisotropic electronic properties of stoichiometric TiH₂ across this transition. Our analysis of the density of states reveals that t2g states induce an electronic instability at low temperatures, triggering the cubic-to-tetragonal transition. This structural change leads to anisotropic variations in electrical and electronic thermal conductivity along the x, y, and z lattice axes. The calculated effective electrical conductivity from the contribution of all the symmetry axes aligns well with the experimental data reported for titanium hydride samples with high hydrogen content, while the electronic thermal conductivity values show reasonable agreement with low-temperature thermal conductivity measurements. These findings provide fundamental insights into the transport properties of TiH2 and their dependence on its crystalline phase and temperature.
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BibTeX
@article{alvarezguerrero2026anisotropic,
title = {{Anisotropic electrical and thermal conductivity of TiH₂ across its crystalline phase transition: A first-principles study}},
author = {Santiago Alvarez-Guerrero and Jose Ordonez-Miranda},
journal = {Journal of Alloys and Compounds Communications},
year = {2026},
month = oct,
doi = {10.1016/j.jacomc.2026.100286},
url = {https://hal.science/hal-05800472v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Anisotropic electrical and thermal conductivity of TiH₂ across its crystalline phase transition: A first-principles study
AU - Santiago Alvarez-Guerrero
AU - Jose Ordonez-Miranda
PY - 2026
DA - 2026/10/15
JO - Journal of Alloys and Compounds Communications
DO - 10.1016/j.jacomc.2026.100286
UR - https://hal.science/hal-05800472v1
AB - Titanium dihydride (TiH₂) undergoes a reversible phase transition from a face-centered tetragonal (fct) to a face-centered cubic (fcc) structure near 310 K, driven by temperature-dependent changes in its c/a lattice parameter ratio. Using first-principles density functional theory (DFT) and Boltzmann transport theory, we investigate the anisotropic electronic properties of stoichiometric TiH₂ across this transition. Our analysis of the density of states reveals that t2g states induce an electronic instability at low temperatures, triggering the cubic-to-tetragonal transition. This structural change leads to anisotropic variations in electrical and electronic thermal conductivity along the x, y, and z lattice axes. The calculated effective electrical conductivity from the contribution of all the symmetry axes aligns well with the experimental data reported for titanium hydride samples with high hydrogen content, while the electronic thermal conductivity values show reasonable agreement with low-temperature thermal conductivity measurements. These findings provide fundamental insights into the transport properties of TiH2 and their dependence on its crystalline phase and temperature.
SN - 2950-2845
ER -