Quantum transport properties in Datta-Das tuned opacity spin-transistors

TL;DR

This paper models a Datta-Das spin transistor to analyze quantum transport and conductance oscillations, highlighting device operation points and spin-flip times, with implications for spintronic device feasibility.

Contribution

It refines previous models by including medium opacity changes and provides detailed analysis of conductance oscillations and spin-flip times in a spin transistor.

Findings

Significant spin-resolved conductance oscillations near barrier heights

Feasibility of device operation based on electric field modulation

Spin-flip times are much shorter than typical spin relaxation times

Abstract

We studied the spin-dependent quantum transport properties using a simple modelling of a Datta-Das spin transistor. We refine previous results by accounting the propagation medium changes of opacity felt by itinerant electrons, when the gate-voltage is switched on and modelling them via the transversal energy levels mismatch. Monitoring the topological-dependent conductance, we are able to identify the device operating points. If the incoming electrons energy approaches the biased-induced barriers height, the spin-resolved conductance oscillations become significant. In a zero temperature picture, our computations of the spin-dependent conductance as function of the electric field at the region below the gate electrode suggest the feasibility of the modeled device. Although we demonstrate that phase time may not be spin-resolved, our simulation allows us to evaluate the time that takes an electron to experience a spin-flip process, resulting in an order of magnitude lower than typical values of the spin relaxation times.