Nonreciprocity in Thermal and Thermoelectric Transport of Electrons in Noncentrosymmetric Crystals

A system with broken inversion symmetry shows direction-dependent conduction phenomena beyond linear response regime, which is referred to as nonreciprocal transport. In a single crystalline system, noncentrosymmetric crystal structure serves as a source of the nonreciprocal transport of the electrons. In this study, the nonlinear thermal and thermoelectric conductivities of electronic systems are calculated up to the second order in an electric field and a temperature gradient by using the Boltzmann equation with the relaxation time approximation. All the second-order conductivities are described by a small number of functions including the Berry curvature dipole. The second-order conductivities are estimated for the 1H monolayer of the transition metal dichalcogenides and a polar semiconductor BiTeX(X=I,Br).