Effect of hetero‐interface on weak localization in InSb thin film layers

Abstract

Magnetoresistance (MR) effects caused by the quantum interference have been investigated in the InSb thin films grown on GaAs(100) substrates by MBE. The positive MR arising from the weak anti-localization (WAL) found in the accumulation layer at the InSb/GaAs interface for a 0.1 µm thick undoped film has been explained by taking account of the spin-Zeeman effect on spin-orbit interaction (SOI) caused by the asymmetric potential at the hetero interface (Rashba term) with SO scattering rate τso–1 ∼ 1.7 × 1012 s–1 from the fits of MR. In Sn-doped films, the negative MR found in extremely weak magnetic fields crossovers to the positive MR with decreasing the film thickness from d = 1 µm to 0.1 µm. These results have been analyzed using a two-layer model for the films; the SO scattering rate in the intrinsic InSb film due to the bulk inversion asymmetry (Dresselhaus term) has been found to be as small as τso–1 ≤ 2 × 109 s–1 and when the interface is approached in the film the WL crossovers to the WAL with the increase of SOI in the layers caused by the increased influence of the Rashba electric field. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)