Defect liquids in a weakly imbalanced bilayer Wigner crystal

In a density-imbalanced bilayer Wigner crystal, where the ratio of electron densities in separate layers deviates slightly from unity, defects spontaneously form in one or both layers in the ground state of the system. Due to quantum tunneling, these defects become mobile and the system becomes a defect liquid. Motivated by this idea, we numerically study the semiclassical energetics of individual and paired point defects in the bilayer Wigner crystal system. We use these results in combination with a simple defect model to map the phase diagram of the defect liquid as a function of electron density and interlayer distance. Our results should be relevant for present experimental bilayer Wigner crystal systems.