Effect of Strain on the Lattice Thermal Conductivity in SrTiO3 from First‐Principles Calculations

Thermal transport plays an important role in the performance of various microelectronic and energy‐conversion devices. In a recent experiment, Sarantopoulos et al. find that the thermal conductivities of epitaxial thin films can be significantly reduced by about 60% under in‐plane tensile strain and they speculate that the strain‐induced ferroelectric domains greatly increase phonon scattering, thereby reducing the thermal conductivity [Physical Review Materials 4, 054 002 (2020)]. Here, theoretical studies on the lattice thermal conductivities of strained and unstrained by first‐principles calculations and self‐consistent phonon theory are carried out. It is found that whether is under compressive or tensile strain, the in‐plane and out‐of‐plane thermal conductivities of strained are all smaller than that of the unstrained one. However, the decrease of thermal conductivities does not exceed 20% under a ±1.5% in‐plane strain, which is not consistent with the experiment. This work shows that strain engineering is not an effective method to tune the intrinsic thermal conductivity of . However, the thermal conductivity of can still be greatly tuned by some other means, such as ferroelectric domains.