The role of spin-orbit interaction in low thermal conductivity of Mg3Bi2
Journal
Applied Physics Letters
Journal Volume
123
Journal Issue
25
Start Page
252109
ISSN
10773118
00036951
Date Issued
2023
Author(s)
Abstract
Three-dimensional layered Mg3Bi2 has emerged as a thermoelectric material due to its high cooling performance at ambient temperature, which benefits from its low lattice thermal conductivity and semimetal character. However, the semimetal character of Mg3Bi2 is sensitive to spin-orbit coupling (SOC). Thus, the underlying origin of low lattice thermal conductivity needs to be clarified in the presence of the SOC. In this work, the first-principles calculations within the two-channel model are employed to investigate the effects of the SOC on the phonon-phonon scattering on the phonon transport of Mg3Bi2. Our results show that the SOC strongly reduces the lattice thermal conductivity (up to ? 35 %). This reduction originates from the influence of the SOC on the transverse acoustic modes involving interlayer shearing, leading to weak interlayer bonding and enhancement anharmonicity around 50 cm?1. Our results clarify the mechanism of low thermal conductivity in Mg3Bi2 and support the design of Mg3Bi2-based materials for thermoelectric applications.
Subjects
Binary Alloys
Bismuth Alloys
Crystal Lattices
Magnesium Alloys
Cooling Performance
First Principle Calculations
Lattice Thermal Conductivity
Low Thermal Conductivity
Phonon-phonon Scattering
Spin-orbit Couplings
Spin-orbit Interaction
Thermo-electric Materials
Thermoelectric Material
Two-channel Model
Phonons
SDGs
Publisher
American Institute of Physics Inc.
Type
journal article