Quantum Phases in Partially Filled Landau Levels

TL;DR

This paper investigates various electron solid and liquid phases in partially filled Landau levels, explaining phase transitions and reentrant quantum Hall effects through energy comparisons and identifying observable phenomena.

Contribution

It provides a detailed analysis of phase transitions between electron solids and liquids in Landau levels, highlighting their role in quantum Hall phenomena.

Findings

Multiple phase transitions between electron solids and liquids.

Observation of phase coexistence in specific Landau-level filling ranges.

First-order phase transitions explain reentrant quantum Hall effects.

Abstract

We compare the energies of different electron solids, such as bubble crystals with triangular and square symmetry and stripe phases, to those of correlated quantum liquids in partially filled intermediate Landau levels. Multiple transitions between these phases when varying the filling of the top-most partially filled Landau level explain the observed reentrance of the integer quantum Hall effect. The phase transitions are identified as first-order. This leads to a variety of measurable phenomena such as the phase coexistence between a Wigner crystal and a two-electron bubble phase in a Landau-level filling-factor range $4.15 < nu < 4.26$, which has recently been observed in transport measurements under micro-wave irradiation.