Electron-spin resonance in the two-dimensional electron gas of GaAs-AlxGa1-xAs heterostructures

Abstract

Electron-spin resonance affects the magnetoresistivity of GaAs-AlxGa1-xAs heterostructures. With microwave frequencies of up to 70 GHz we studied systematically the spin splitting of the Landau levels in magnetic fields up to 14.5 T. The resonances within a certain Landau level are only observed at magnetic field values where the Fermi level is located between the corresponding spin levels. The spin splitting of a Landau level is an exact quadratic function of the magnetic field and its extrapolation to zero magnetic field leads to vanishing spin splitting. The g factors depend on the magnetic field and the Landau level index as follows: g(B,N)=g0-c(N+(1/2)B, where g0 and c are sample-dependent constants. © 1988 The American Physical Society.