Rashba spin-orbit interaction of In0.53Ga0.47As/In0.7Ga0.3As/In0.53Ga0.47As shallow two-dimensional electron gas by surface etching

We have investigated Rashba spin-orbit interaction (SOI) of In0.53Ga0.47As/In0.7Ga0.3As/In0.53Ga0.47As two dimensional electron gas (2DEG) located below 6.4 nm - 26.5 nm from the sample surface by analyzing weak antilocalization (WAL). Depth of the 2DEG from the sample surface is systematically controlled by surface etching within the identical samples. WAL is enhanced as increasing the etching depth due to the large energy-band bending of In0.53Ga0.47As/In0.7Ga0.3As/In0.53Ga0.47As quantum well. The Rashba SOI parameter α increases with increasing the etching depth, and 2.41 x 10-12 eVm is obtained in the shallowest 2DEG which is located below 6.4 nm from the surface. Calculated α from the k.p formalism shows good agreement on the surface etching dependence with the experimental values. Dominant contribution of the Rashba SOI parameter α is originated from the In0.53Ga0.47As/In0.7Ga0.3As heterointerface as well as the energy-band bending in the In0.7Ga0.3As quantum well. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)