Large Rashba splitting in InAs quantum wells due to electron wave function penetration into the barrier layers.
We report on zero-field spin splitting of two-dimensional electron systems. Though absent in the unbiased InAs square asymmetric quantum well (SAQW), the Rashba splitting becomes pronounced by applying a positive back-gate voltage. In our SAQW, the Rashba parameter alpha increases with electron density and is tuned by a factor of about 2 using an additional front gate without charging the well. We argue that the band-edge profile provides the important contribution for spin-orbit interaction due to barrier penetration of the envelope wave function. This mechanism can provide the potential for high speed implementation in spintronics.
Grundler
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Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany.