The influence of twin boundary on lattice thermal conductivity of thermoelectric InSb

Twin boundaries (TBs) can increase interface scattering to reduce the lattice thermal conductivity. InSb has good electronic transport properties, but its high thermal conductivity constrains its thermoelectric application. In this work, we aim to study the role of TBs on lattice thermal conductivity of InSb. We use non-equilibrium molecular dynamics simulation to investigate how the TB spacing and orientation influence the lattice thermal conductivity of InSb. We find that TBs can hinder the heat flow, leading to decreased temperature gradient and, hence, remarkably reduced lattice thermal conductivity. The relationship between kappa(L) and lambda can be described by a proportional function. Nanotwinned InSb with TB spacing of 1.1 nm has a lattice thermal conductivity of 12.6 W/m K, a decrease in 22.2% compared with its single crystal (16.2 W/m K). We also find that a minimum lattice thermal conductivity of InSb can be obtained when the TB orientation is perpendicular to the direction of heat flow. These findings provide a theoretical guidance for TBs engineering to reduce the thermal conductivity of thermoelectric materials.