Phonon thermal transport properties of XB <sub>2</sub> (X = Mg and Al) compounds: considering quantum confinement and electron–phonon interaction
Sen Liu, Zheng Chang, Xiaoliang Zhang, Kunpeng Yuan, Yufei Gao, Dawei Tang
Abstract
Abstract XB 2 (X = Mg and Al) compounds have drawn great attention for their superior electronic characteristics and potential applications in semiconductors and superconductors. The study of phonon thermal transport properties of XB 2 is significant to their application and mechanism behind research. In this work, the phonon thermal transport properties of three‐dimensional (3D) and two‐dimensional (2D) XB 2 were studied by first‐principles calculations. After considering the electron–phonon interaction (EPI), the thermal conductivities (TCs) of 3D MgB 2 and 3D AlB 2 decrease by 29% and 16% which is consistent with experimental values. Moreover, the underlying mechanisms of reduction on lattice TCs are the decrease in phonon lifetime and heat capacity when considering quantum confinement effect. More importantly, we are surprised to find that there is a correlation between quantum confinement effect and EPI. The quantum confinement will change the phonon and electron characteristics which has an impact on EPI. Overall, our work is expected to provide insights into the phonon thermal transport properties of XB 2 compounds considering EPI and quantum confinement effect.