A Hot Electron Thermocouple and the Diffusion Thermopower of Two-Dimensional Electrons in GaAs

TL;DR

This paper introduces a simple hot electron thermocouple for measuring the diffusion thermopower of a 2D electron system in GaAs, providing results consistent with the Mott formula up to 2 K with less phonon-drag sensitivity.

Contribution

A novel hot electron thermocouple technique for 2DES thermopower measurement that avoids micron-scale patterning and reduces phonon-drag effects.

Findings

Thermopower results agree with Mott formula up to 2 K.

Technique is less sensitive to phonon-drag effects.

No micron-scale patterning required.

Abstract

A simple hot electron thermocouple is realized in a two-dimensional electron system (2DES) and used to measure the diffusion thermopower of the 2DES at zero magnetic field. This hot electron technique, which requires no micron-scale patterning of the 2DES, is much less sensitive than conventional methods to phonon-drag effects. Our thermopower results are in good agreement with the Mott formula for diffusion thermopower for temperatures up to T ~ 2 K.