Effect of current hysteresis on the spin polarization of current in a paramagnetic resonant tunneling diode

TL;DR

This study investigates spin-dependent quantum transport in a paramagnetic resonant tunneling diode, revealing two types of current hysteresis and conditions for nearly full spin polarization, which are promising for spintronics applications.

Contribution

The paper introduces a detailed analysis of current hysteresis types and spin polarization behavior in a paramagnetic RTD using the Wigner-Poisson method, highlighting new insights into spin-dependent transport phenomena.

Findings

Two types of current hysteresis are identified in the I-V characteristics.

Conditions for nearly full spin polarization are established.

Hysteresis is linked to electron accumulation and quasi-bound state formation.

Abstract

A spin-dependent quantum transport is investigated in a paramagnetic resonant tunneling diode (RTD) based on a Zn$_{1-x}$Mn$_x$Se/ZnBeSe heterostructure. Using the Wigner-Poisson method and assuming the two-current model we have calculated the current-voltage characteristics, potential energy profiles and electron density distributions for spin-up and spin-down electron current in an external magnetic field. We have found that -- for both the spin-polarized currents -- two types of the current hysteresis appear on the current-voltage characteristics. The current hysteresis of the first type occurs at the bias voltage below the resonant current peak and results from the accumulation of electrons in the quantum well layer. The current hysteresis of the second type appears at the bias voltage above the resonant current peak and is caused by the creation of the quasi-bound state in the left contact region and the resonant tunneling through this quasi-bound state. The physical interpretation of both the types of the current hysteresis is further supported by the analysis of the calculated self-consistent potential profiles and electron density distributions. Based on these results we have shown that -- in certain bias voltage and magnetic field ranges -- the spin polarization of the current exhibits the plateau behavior with the nearly full spin polarization. This property is very promising for possible applications in spintronics.