MEAN-FIELD THEORY FOR THE SPIN-TRIPLET EXCITON LIQUID IN QUANTUM-WELLS

Using a mean-field theory, we study the possible existence of a spin-t riplet intersubband exciton liquid ground state in semiconductor quant um well systems as a function of the electronic density and the streng th of the intersubband Coulomb interaction matrix element at low tempe ratures. We find the excitonic phase to be stable over a large region of parameter space, and our calculated critical temperatures are attai nable experimentally. In addition, we find that the transition to the excitonic phase can be either first- or second-order at zero temperatu re.