Zero field spin splitting in indium gallium arsenide/indium aluminum arsenide heterostructures
Abstract
The InGaAs/InAlAs heterojunction is a promising material system for high speed device applications and opto-electronic integration. From beating effects observed in Shubnikov-de Haas (SdH) oscillations it is demonstrated that the degeneracy of the conduction band is lifted in zero magnetic field in this material system. The SdH oscillations observed in two pseudomorphic samples and one lattice matched sample show clear beats with up to six null points for magnetic fields B less than 1T. This field is low enough that the effect of non-parabolicity is deemed insignificant. Zero field spin splittings of 1.5-2.75meV were obtained for the three samples. Two mechanisms produce zero field spin splitting in semiconductor heterostructures: (i) a k-cube term arising from crystal inversion asymmetry and (ii) the Rashba term due to interface-spin-orbit-interaction. It is demonstrated that in this material system only one of these mechanisms is dominant and that it is probably the Rashba term. From investigation of the spin splitting in a tilted magnetic field, negative g-factors for 2-3 are obtained for these materials.
Degree
Ph.D.
Advisors
Datta, Purdue University.
Subject Area
Electrical engineering
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