Theoretical evidence of spontaneous spin polarization in GaAs/AlGaAs split-gate heterostructures

Abstract

Spintronics is a new branch of electronics which utilizes the spin degree of freedom of an electron rather than the charge, as used in conventional devices. This paradigm by itself provides a huge potential in, for example, high density memories, non volatile reprogrammable logic, quantum computing and various other applications. Extensive research has been going on in the spintronic field to overcome variety of challenges posed in the form of efficient injection, transport and detection of spin polarized carriers from one material to another, etc. To validate the spin splitting in device heterostructures, various conductance measurements have been performed on quantum point contacts (QPC) formed by a lateral confinement of a high mobility two-dimensional electron gas in a modulation doped GaAs/Al/sub x/Ga/sub 1 - x/As heterostructure. It has been found that these structures exhibit additional plateaus (below the first plateau) at 0.7 and 0.25 (2e/sup 2//h). It this work, the spin-polarized density functional theory of Kohn and Sham is used to calculate the spin dependent features of the quantum point contacts and confirm the recent experimental findings within our group.