Electron-spin resonance of the two-dimensional electron gas in Ga_0.47In_0.53As-InP heterostructures

The microwave-induced change of the magnetoresistivity of Ga_0.47In_0.53As-InP heterostructures reveals resonant structure which is attributed to electron-spin resonance of the two-dimensional conduction electrons. With microwave frequencies up to 480 GHz and in magnetic fields up to 12 T, we studied the spin splitting of the two lowest Landau levels in different samples. The spin splitting of these Landau levels is a 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 B and the Landau level N as follows: g(B,N)=g₀-c(N+1/2)B, where g₀ and c are sample-dependent parameters, which are of the order of g₀≊4.1 and c≊0.08 T^-1, in the studied heterostructures.