Molecular dynamics study of a classical two-dimensional electron system: Positional and orientational orders

TL;DR

This study uses molecular dynamics simulations to analyze the phase behavior of a 2D electron system, revealing quasi-long-range positional order and long-range orientational order, consistent with the hexatic phase predicted by KTHNY theory.

Contribution

It provides detailed simulation evidence of the phase structure and order types in a classical 2D electron system, supporting the existence of the hexatic phase.

Findings

Quasi-long-range positional order in the solid phase.

Long-range orientational order observed.

Evidence supporting the hexatic phase hypothesis.

Abstract

Molecular dynamics simulation is used to investigate the crystallization of a classical two-dimensional electron system, in which electrons interact with the Coulomb repulsion. From the positional and the orientational correlation functions, we have found an indication that the solid phase has a quasi-long-range (power-law correlated) positional order and a long-range orientational order. This implies that the long-range 1/r system shares the absence of the true long-range crystalline order at finite temperatures with short-range ones for which Mermin's theorem applies. We also discuss the existence of the ``hexatic'' phase predicted by the Kosterlitz-Thouless-Halperin-Nelson-Young theory.