Suppression of thermopower and enhancement of thermal conductivity in bulk topological insulators

The decrease in the Seebeck coefficient with increasing magnetic field and the rapid enhancement of thermal conductivity in longitudinal thermoelectric transport are often regarded as hallmark responses of the chiral anomaly. In this work, we investigate the thermoelectric responses of bulk topological insulators using the semiclassical Boltzmann transport equation. Our findings reveal that the Berry curvature can also induce a quadratic suppression of thermopower and a significant enhancement of thermal conductivity in systems without chirality, particularly when the chemical potential is near the band edge. These conclusions are broadly applicable to various topological insulators. Compared with ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$, the pronounced band inversion in the conduction band of ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$ results in a distinct kink structure near the Van Hove singularity. Additionally, the sign of the $g$ factor has a strong influence on the signs of the thermoelectric coefficients. Our study highlights new challenges in identifying transport signatures of the chiral anomaly in topological semimetals and provides deeper insights into the thermoelectric transport behavior of topological materials influenced by Berry curvature.