Thermoelectric Current and Coulomb-Blockade Plateaus in a Quantum Dot

TL;DR

This paper investigates thermoelectric currents in a quantum dot using a generalized master equation, revealing sign-changing currents and Coulomb blockade effects beyond linear response.

Contribution

It introduces a method combining GME and exact diagonalization to analyze thermoelectric effects in quantum dots beyond linear response.

Findings

Current exhibits saw-tooth profile with plateaus of near-zero current.

Thermoelectric behavior depends on chemical potential and Coulomb interactions.

Results align with known linear response thermopower but extend beyond it.

Abstract

A Generalized Master Equation (GME) is used to study the thermoelectric currents through a quantum dot in both the transient and steady-state regime. The two semi-infinite leads are kept at the same chemical potential but at different temperatures to produce a thermoelectric current which has a varying sign depending on the chemical potential. The Coulomb interaction between the electrons in the sample is included via the exact diagonalization method. We observe a saw-teeth like profile of the current alternating with plateaus of almost zero current. Our calculations go beyond the linear response with respect to the temperature gradient, but are compatible with known results for the thermopower in the linear response regime.