We report a thermal transport study of IrSbSe, which crystallizes in a noncentrosymmetric cubic structure with the P213 space group and shows a narrow-gap semiconducting behavior. The large discrepancy between the activation energy for conductivity [Eρ = 128(2) meV] and for thermopower [ES = 17.7(9) meV] from 200 to 300 K indicates the polaronic transport mechanism. Electrical resistivity varies as exp(T0/T)1/4 and thermopower varies as T1/2 at low temperatures, indicating that it evolves into the Mott's variable-range hopping dominant conduction with decreasing temperature. IrSbSe shows relatively low value of thermal conductivity (∼ 1.65 W/K⋅m) and thermopower of about 0.24 mV/K around 100 K, yet poor electrical conductivity. On the other hand, high vacancy defect concentration on both Ir and Sb atomic sites of up to 15\%, suggests high defect tolerance and points to possibility of future improvement of carrier density by chemical substitution or defect optimization.
@article{arxiv.2210.16447,
title = {Thermal transport properties of IrSbSe},
author = {Yu Liu and Milinda Abeykoon and Niraj Aryal and David Graf and Zhixiang Hu and Weiguo Yin and C. Petrovic},
journal= {arXiv preprint arXiv:2210.16447},
year = {2022}
}