Low-Temperature Thermopower in CoSbS

TL;DR

This study reports giant low-temperature thermopower in CoSbS crystals, linked to electronic correlations and magnetic effects, with potential implications for thermoelectric applications.

Contribution

It reveals the mechanism of giant thermopower in CoSbS, highlighting the role of electronic correlations and magnetic field effects, which is a novel insight.

Findings

Giant thermopower of 2.5 mV/K observed in CoSbS

Magnetic field influences low-temperature thermopower

Electronic correlations contribute to thermopower enhancement

Abstract

We report giant thermopower S = 2.5 mV/K in CoSbS single crystals, a material that shows strong high-temperature thermoelectric performance when doped with Ni or Se. Changes of low temperature thermopower induced by magnetic field point to mechanism of electronic diffusion of carriers in the heavy valence band. Intrinsic magnetic susceptibility is consistent with the Kondo- Insulator-like accumulation of electronic states around the gap edges. This suggests that giant thermopower stems from temperature-dependent renormalization of the non-interacting bands and buildup of the electronic correlations on cooling.