Voltage-controlled tunneling anisotropic magneto-resistance of a ferromagnetic $p^{++}$-(Ga,Mn)As/$n^{+}$-GaAs Zener-Esaki diode

TL;DR

This study demonstrates large tunneling anisotropic magneto-resistance in a ferromagnetic (Ga,Mn)As/n-GaAs diode, showing tunable and bias-dependent anisotropic transport properties over various temperatures and voltages.

Contribution

It reveals the bias-dependent and tunable nature of tunneling anisotropic magneto-resistance in a single ferromagnetic diode, highlighting the role of bias polarity and voltage in modulating transport.

Findings

Large tunneling anisotropic magneto-resistance observed.

Bias modifies tunnel transparency and anisotropic transport.

Opposite contributions from two subbands under different bias directions.

Abstract

The large tunneling anisotropic magneto-resistance of a single $p^{++}$-(Ga,Mn)As/$n^{+}$-GaAs Zener-Esaki diode is evidenced in a perpendicular magnetic field over a large temperature and voltage range. Under an applied bias, the tunnel junction transparency is modified, allowing to continuously tune anisotropic transport properties between the tunneling and the ohmic regimes. Furthermore, an asymmetric bias-dependence of the anisotropic tunneling magneto-resistance is also observed: a reverse bias highlights the full (Ga,Mn)As valence band states contribution, whereas a forward bias only probes part of the density of states and reveals opposite contributions from two subbands.