Diffusion thermopower of (Ga,Mn)As/GaAs tunnel junctions

TL;DR

This paper reports the discovery of tunneling anisotropic magnetothermopower in (Ga,Mn)As/GaAs junctions, revealing a voltage response to temperature differences that depends on magnetization direction, with implications for spintronic device operation.

Contribution

It introduces the observation of tunneling anisotropic magnetothermopower in magnetic semiconductor junctions, linking voltage response to the density of states derivative and magnetization orientation.

Findings

Voltage response is strongly anisotropic with magnetization direction.

The effect relates to the energy derivative of the density of states.

Implications for understanding spin injection in semiconductor devices.

Abstract

We report the observation of tunneling anisotropic magnetothermopower, a voltage response to a temperature difference across an interface between a normal and a magnetic semiconductor. The resulting voltage is related to the energy derivative of the density of states in the magnetic material, and thus has a strongly anisotropic response to the direction of magnetization in the material. The effect will have relevance to the operation of semiconductor spintronic devices, and may indeed already play a role in correctly interpreting the details of some earlier spin injection studies.