Spin aligned exciton gas in uniaxially compressed Ge

Abstract

It is shown that the unique opportunity for investigation of the statistical behaviour of a spin aligned exciton gas up to high densities corresponding to rs≈2 at T≈2K in strongly uniaxially compressed Ge in magnetic field is arised. The experimentally observed changes in the exciton-phonon emission spectra of a dense exciton gas are interpreted in terms of the weakly nonideal Bose-gas. The ionization collapse (Mott transition) of excitons giving rise to an abrupt change in electron transport phenomena has been observed at density corresponding to rs=2.