Exciton supersolidity in hybrid Bose-Fermi systems
  We investigate the ground states of a Bose-Einstein condensate of indirect excitons coupled to an electron gas. We show that in a properly designed system, the crossing of a roton minimum into the negative energy domain can result in the appearance of the supersolid phase, characterized by periodicity in both real and reciprocal space. Accounting for the spin-dependent exchange interaction of excitons we obtain ferromagnetic supersolid domains. The Fourier spectra of excitations of weakly perturbed supersolids show pronounced diffraction maxima which may be detected experimentally. 
Michal Matuszewski, Thomas Taylor and Alexey V. Kavokin
cond-mat.mes-hall cond-mat.quant-gas