Anatomy of the quantum melting of the two dimensional Wigner crystal

TL;DR

This paper investigates the quantum melting process of a two-dimensional Wigner crystal, confirming the existence of a hybrid phase at intermediate densities and discussing its implications for various transition scenarios.

Contribution

It provides a detailed analysis of the hybrid phase stability and confirms its existence in the thermodynamic and continuum limits, refining understanding of the phase transition.

Findings

Hybrid phase is more stable than liquid and crystal at rs=31.5

Stability linked to the hybrid phase's delocalized nature

Results impact theories on quantum phase transition scenarios

Abstract

The Fermi liquid-Wigner crystal transition in a two dimensional electronic system is revisited with a focus on the nature of the fixed node approximation done in quantum Monte Carlo calculations. Recently, we proposed (Phys. Rev. Lett. 94, 046801 (2005)) that for intermediate densities, a hybrid phase (with the symmetry of the crystal but otherwise liquid like properties) is more stable than both the liquid and the crystal phase. Here we confirm this result both in the thermodynamic and continuum limit. The liquid-hybrid transition takes place at rs=31.5 +/- 0.5. We find that the stability of the hybrid phase with respect to the crystal one is tightly linked to its delocalized nature. We discuss the implications of our results for various transition scenarii (quantum hexatic phase, supersolid, multiple exchange, microemulsions) proposed in the literature.