Quantum structural transformation of correlation-induced electron solids in two-dimensional MoS2 double layers

We investigated the properties of quantum electron solids of different symmetries in two-dimensional doublelayer systems in transition-metal dichalcogenides stacked on opposite sides of thin layers of boron nitride. For the parameters of our experimental structure with a screened interaction, we discovered that both the hexagonal and the square lattices are stable, whereas for a pure Coulomb interaction with no screening, only the hexagonal lattice is stable. The hexagonal lattice possesses an energy lower than that of the square lattice and thus is expected to form at low temperatures. We found that the square lattice has a higher melting temperature and thus will replace the hexagonal lattice of the electron solid state as the temperature is increased. This result agrees with our Coulomb drag resistance measurements at different temperatures which exhibit peaks at different gate voltages, corresponding to phases with different chemical potentials. Our system provides for a system to study quantum structural transformations.

Automated summary

We investigated the properties of quantum electron solids of different symmetries in two-dimensional double-layer systems. We found that both hexagonal and square lattices are stable, but only the hexagonal lattice is stable in the case of pure Coulomb interaction. The square lattice will replace the hexagonal lattice as the temperature increases.