Phase transitions in a strongly interacting electron system under confinement

Phase transition in a two-dimensional lattice is described by a Berezinskii-Kosterlitz-Thouless (BKT) mechanism. At low temperatures the ground state of strongly interacting 2D electron system is a Wigner solid, which was experimentally observed in a many experiments with electrons on the surface of liquid helium. A well controlled system of electrons on liquid helium provide an excellent platform to investigate a many-body phenomena. Here we investigate the influence of a quasi-one-dimensional confinement on the structural order and melting of electrons on helium experimentally and by numerical simulations. In the experiments electrons are confined by electrostatic potential in a microchannel structures. By tuning voltages on gate electrodes we were able to demonstrate the control of number of electron rows (from a single chain up to 25 rows). We show that for small number of rows gamma parameter (the ratio of Coulomb energy to thermal energy) is suppressed, while for large number of rows a BKT theory prediction is recovered. We compare the results with molecular dynamics simulations. The temperature dependence of topological defects density, translational correlation function and structure factor were calculated and discussed in the context of BKT transition.