DETERMINATION OF THE SIGN OF THE CONDUCTION-ELECTRON G-FACTOR IN SEMICONDUCTOR QUANTUM-WELLS BY MEANS OF THE HANLE EFFECT AND SPIN-QUANTUM-BEAT TECHNIQUES

A method of measuring the sign of the conduction-electron g factor in semiconductor quantum-wells is proposed, based on determination of the sense of electron-spin Larmor precession by the Hanle effect or spin- quantum-beat techniques under oblique incidence of pump light on the s ample, with the luminescence detected at an angle to the pump beam. Th is method has been used to measure the sign of the transverse electron ic g-factor component in GaAs/Al0.3Ga0.7As quantum-wells of various wi dths. It has been shown experimentally that the average spin of electr ons photocreated in quantum-wells may not coincide with the pump light direction. Expressions for the oscillations of the luminescence circu lar polarization in the spin-quantum-beat regime and in the Hanle effe ct have been obtained, taking into account the electron spin relaxatio n anisotropy. (C) 1997 American Institute of Physics.