Micro- and nanocrystalline, porous, composite semiconductors

Modeling the properties of MgAgSb, a promising thermoelectric material for use in the temperature range of 300–600 K

V. G. Orlov, G. S. Sergeev, A. A. Ivanov

National Research Centre "Kurchatov Institute", Moscow

Abstract: Using the WIEN2k program, based on the density functional method, the electronic structure of the tetragonal $\alpha$- and $\beta$-phases and two variants of the cubic $\gamma$-phases of the MgAgSb compound was calculated. From the calculation results it follows that the structural phase transitions in MgAgSb are accompanied by semiconductor-metal electronic transitions. Analysis of the features in the spatial distribution of the charge density of the $\alpha$-, $\beta$- and $\gamma$-phases showed the absence of covalent bonding in MgAgSb, which can explain the presence of several structural phase transitions over a small temperature range. Using the phonopy and phono3py programs, the phonon spectra of the $\gamma$-phase of MgAgSb, as well as its lattice thermal conductivity in the temperature range from 300 to 1000 K, were calculated. The IRelast program made it possible to find for all MgAgSb phases both the values of the elastic constants $C_{ij}$ and the values of the main strength characteristics – shear moduli, compression moduli, Young’s modulus, Poisson’s ratio, Vickers hardness, and universal indices of elastic property anisotropy. Basing on the analysis of the obtained data, it was concluded that the $\alpha$-phase of MgAgSb has the best mechanical properties.

Received: 24.09.2025
Revised: 10.10.2025
Accepted: 05.11.2025

DOI: 10.61011/FTP.2025.07.62007.8590