Phase Transition in Two-Dimensional Electron-Hole Systems in High Magnetic Fields and Their Effect on Cyclotron Resonance Spectra

Abstract

Quasi-two-dimensional electron-hole (e-h) systems in high transverse magnetic fields are considered for the case when only the lowest Landau level is occupied. A first order phase transition with the formation of e-h liquid is shown to be possible in the system. It turns out that in the zero order of the small parameter of the theory developed, this transition is thermodynamically equivalent to two second order transitions with the formation of an excitonic phase. The excitonic phase can microscopically be distinguished from the drop state by the cyclotron resonance spectra.