Insights into strain dependent lattice thermal conductivity of tin oxide

Mechanical strain is expected to impact the lattice thermal conductivity of crystalline solids by modifying lattice vibration properties. Tin oxide is one key base material in the family of transparent conducting oxides, and its thermal transport properties are of technological importance to device performance. In this work, we investigate the lattice thermal transport of tin oxide (SnO ₂ ) under uniaxial strain by solving the phonon Boltzmann transport equation based on first-principles calculations. We find that the lattice thermal conductivity of tin oxide decreases monotonically as moving from uniaxial compression to tension. We disclose that strain affects remarkably the phonon group velocity and lifetime of optical modes, with two dominant optical modes identified. The behavior is in-depth understood by looking into the influence of strain on the number of the allowed three-phonon scattering processes, lattice anharmonicity, and bonding strength. This work provides quantitative understanding of strain dependent thermal conductivity of tin oxide, with insights into the strain effect on phonon properties of bulk crystalline materials.