Violation of the T−1 Relationship in the Lattice Thermal Conductivity of Mg3Sb2 with Locally Asymmetric Vibrations
(a) Absolute values of the 3rd-order IFCs of various combinations of atoms. (b) The MD trajectories at 300 K and 700 K. The green dashed box is the primitive cell of Mg3Sb2, and the blue and orange arrows represent the directions we adopted for the following energy and force calculations. (c) Energy-distance curve for Mg2 atoms when Mg2 atom is displaced away from its equilibrium position along the -axis. (d) Same as (c) but for the force-distance curve. Two-headed horizontal arrows in (d) indicate, respectively, the evenly distributed small (1) displacements and unevenly distributed large (2) displacements.