Spin Polarization in GaAs/Al0.24Ga0.76As Heterostructures

Keywords:
0.7 anomaly, spin polarization, LDA

Abstract:
Spintronics is a new branch of electronics which involves the active control and manipulation of spin degrees of freedom in solid-state devices. Spin transport differs from charge transport as spin is a non-conserved quantity in solids due to spin-orbit and hyperfine coupling. 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 spintronics field to overcome a 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/AlxGa1-xAs heterostructure. It has been found that these structures exhibit additional plateaus at 0.7 and 0.25 (2e2/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.

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Nanotech 2005 Conference Program Abstract