Atomic-Monolayer Thermoelectric Conversion in Two-Dimensional Chalcogenides

Electronic structures of bismuth telluride, the highest thermoelectric figure of merit at room temperature, are substantially modified by electronic confinements and strong spin-orbit coupling in the few-monolayers thickness regime. Here, by local optical probes, we show direct evidence that efficient thermoelectric current generation is available at the few-monolayers thick bismuth telluride by hot electrons motions through two-dimensional subbands and topologically protected surface states. Our study offers a challenging opportunity to investigate the fundamental photoresponse of topological quantum states, and provides a new design rule for the highly efficient thermoelectric circuitry.