Theoretical calculations on transport properties of high-temperature binary and entropy-stabilized diborides*

High-melting structural diborides such as ZrB₂, TiB₂ and HfB₂ and their entropy-stabilized variants MB₂ (M= transition metals) are materials candidates for high temperature structural applications because of their high melting point, excellent mechanical strength, high electrical and thermal conductivity and thermodynamic stability. In the current study, we employed the Density functional theory (DFT) calculations to model the electron-phonon interactions and related properties including the relaxation time, electrical conductivity, and transport properties. Both low temperature behavior of the thermal conductivity, which is mainly due to the phonon contribution, and high temperature ones, governed by the electron contributions, were calculated. Additionally, we have systematically evaluated the effect of alloying elements such as Ta and Cr on the thermal properties of the diborides and compared them with the experimental results. The support from the Advanced Manufacturing program from the CMMI Division of NSF (Award No. 1902069) is gratefully acknowledged. The computational support from NERSC is highly acknowledged.