  Thermoelectric (TE) refrigeration such as Peltier cooler enables a unique
opportunity in electric energy to directly convert thermal energy. Here, we
propose a TE module with both refrigeration and power generation modes by
utilizing asymmetric surfaces of a magnetic topological insulator (quantum
anomalous Hall insulator) with a periodic array of hollows filled with two
different dielectrics. Based on the Boltzmann transport theory, we show that
its efficiency, i.e., the dimensionless figure of merit ZT exceeds 1 in the
low-temperature regime below 300 K. The proposed device could be utilized as a
heat management device that requires precise temperature control in small-scale
cooling.
