Exciton crystal melting and destruction by disorder in bilayer quantum hall system with total filling factor one

Bilayer quantum hall system with total filling factor 1 was studied in the regime of heavy layer imbalance in a recent transport experiment (Ref. 1), with intriguing new findings. We demonstrate in this paper that 1) the exciton Wigner crystal in this regime can melt into a superfluid phase, giving rise to re-entrant superfluid behavior; 2) in the presence of disorder, electron and hole Wigner crystals in the two layers go through a locking/decoupling transition as layer separation increases, resulting in a sudden change in the counter flow conductance. Comparison will be made with the findings of Ref. 1.