CROSSING OF CYCLOTRON AND SPIN RESONANCES IN A 2D ELECTRON-GAS

We compare anticrossing of the cyclotron and spin resonances in spin-p olarized and non-polarized phases of the degenerate two-dimensional Co ulomb gas subjected to a strong tilted magnetic field. The spin-orbit coupling splits these resonances into three lines with the gaps betwee n them exactly equal to delta2n+1 = v(so)p(F) and delta2n = v(so)p(F)/ square-root 2 at odd- and even- integer filling factors, respectively. The 1/square-root 2 difference between delta2n and delta2n+1 comes fr om the existence of an additional spin-density wave excitation in the polarized phase of interacting electrons at nu = 2n and can be treated as a means to indicate the re-entrance of the system into it.