The field-induced phase transition of an electron-hole system in weakly coupled double quantum wells

The sudden reduction of the photoluminescence linewidth observed at low temperature in coupled quantum wells is analysed in view of possible 2D phase transitions occurring at different density limits. The linewidth calculated within a BCS-like transition is found to be proportional to the gap below Tc. This can be regarded as a 'fingerprint' for identifying the nature of the condensed phase. © 1990 IOP Publishing Ltd.