Magneto-engineering towards high thermoelectric performance in topological insulator Bi88Sb12

Abstract

Abstract High thermoelectric performance is generally achieved by synergistically optimizing two or even three of the contradictorily coupled thermoelectric parameters. Here, we demonstrate magneto-engineering as a strategy to achieve simultaneous gain in enhanced Seebeck coefficient and reduced thermal conductivity. We report giant magneto-Seebeck effect and high magneto-thermoelectric figure of merit of 1.7±0.2 at 180 K and 0.7 T in single-crystalline Bi88Sb12 topological insulator, which fills the gap of high performance below 300 K and can be useful for low temperature thermoelectric applications. The large magneto-Seebeck response was attributed to the distortion of the density of states benefiting from small Fermi surfaces and the ultrahigh mobility originating from the linear Dirac bands. The application of a low magnetic field to achieve high thermoelectric performance can be extended to the rapidly emerging topological materials with similar features because it synergistically optimizes the thermoelectric parameters.