Ultralow thermal conductivity of single crystalline BaTiS3

BaTiS3 (BTS) is a new perovskite-like material that has promising optical, electronic and thermal properties, with potential applications in electronics and thermoelectrics. We report measurements of thermal conductivity of BTS single crystal from 80 K – 300 K using time-domain thermoreflectance. The room temperature thermal conductivity of BTS is found to be 0.5 W m-1 K-1, which is less than 10% of that of commonly known BaTiO3. To understand the origin of such low thermal conductivity we perform ab initio calculations using the temperature dependent effective potential (TDEP) method [1, 2] to study phonon transport at finite temperature. The strong temperature dependence of phonon modes and low group velocities lead to ultralow values of lattice thermal conductivity, supporting the experimental observation.
[1] O. Hellman, I. A. Abrikosov, S. I. Simak. Physical Review B 84, 180301(2011).
[2] O. Hellman, I. A. Abrikosov. Physical Review B 88, 144301(2013).