Extrinsic thermoelectric response of coherent conductors

TL;DR

This paper explores how a scanning probe can induce and control thermoelectric effects in a coherent conductor, revealing nonlocal and diode-like behaviors even without charge injection or electron-hole symmetry breaking.

Contribution

It demonstrates the generation of multiterminal thermoelectric effects and nonreciprocal responses through probe-induced interference in a simple noninteracting electron model.

Findings

Nonlocal thermoelectric response modulated by probe position

Observation of a thermoelectric diode effect

Insights into dephasing and quasielastic scattering mechanisms

Abstract

We investigate the thermoelectric response of a coherent conductor in contact with a scanning probe. Coupling to the probe has the dual effect of allowing for the controlled local injection of heat currents into the system and of inducing interference patterns in the transport coefficients. This is sufficient to generate a multiterminal thermoelectric effect even if the conductor does not effectively break electron-hole symmetry and the tip injects no charge. Considering a simple model for noninteracting electrons, we find a nonlocal thermoelectric response which is modulated by the position of the hot probe tip, and a nonreciprocal longitudinal response which leads to a thermoelectric diode effect. A separate investigation of the effects of dephasing and of quasielastic scattering gives further insights into the different mechanisms involved.