Berlin 2008 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

HL: Fachverband Halbleiterphysik

HL 35: Spin controlled transport II

HL 35.8: Vortrag

Mittwoch, 27. Februar 2008, 16:15–16:30, ER 164

Optimization of InP/GaInAs structures with respect to Rashba spin-orbit coupling — •Masashi Akabori, Markus Hagedorn, Vitaliy Guzenko, Thomas Schäpers, and Hilde Hardtdegen — Institute of Bio- and Nanosystems (IBN-1) and Centre of Nanoelectronic Systems for Information Technology (CNI), Research Centre Jülich, 52425 Jülich, Germany

In this report we investigated the influence of the channel layer thickness on spin-orbit coupling. To this end a modulation doped heterostructure was deposited by MOVPE which consisted of a 350 nm InP buffer, a 10 nm n-supply layer a 20 nm InP spacer, d nm GaInAs channel layer with 77% In content, and a 150-d nm lattice-matched GaInAs sub-channel, and 10 nm InP cap. The channel thickness d was varied between 2 and 10 nm. We first determined the mobility at room temperature and 77K with van der Pauw geometry: it decreases monotonically with the channel thickness. The result is reasonable because the thinner the channel becomes, the more the electron wave function extends into the GaInAs lattice matched sub-channel. In magnetoresistance measurements around 0.5K, we confirmed a clear shift of the first node position toward high magnetic field in a Hall-bar of the 2 nm channel sample, which indicates large Rashba spin-orbit coupling in spite of the thin high indium content channel. The behavior also agreed well with the theoretical estimation from the calculated band profile of the heterostructure, therefore the Rashba spin-orbit coupling in our InP/GaInAs heterostructures can be enhanced by tuning the channel layer thickness.