Roton Instabilities and Wigner Crystallization of Rotating Dipolar Fermions in the Fractional Quantum Hall Regime

TL;DR

This paper investigates the stability of Laughlin liquids of rotating dipolar fermions, revealing instabilities at certain filling factors and proposing the formation of Wigner crystals in those regimes.

Contribution

It identifies the conditions under which Laughlin liquids become unstable and predicts the emergence of Wigner crystals at specific filling factors in the fractional quantum Hall regime.

Findings

Laughlin liquids are unstable for filling factors ≤ 1/7 due to roton minima becoming negative.

Instabilities lead to the formation of correlated Wigner crystals at low filling factors.

The study extends understanding of phase transitions in rotating dipolar fermion systems.

Abstract

We point out the possibility of occurring instabilities in Laughlin liquids of rotating dipolar fermions with zero thickness. Previously such a system was predicted to be the Laughlin liquid for filling factors being greater and equal to 1/7. However, from intra-Landau-level excitations of the liquid in the single-mode approximation, the roton minima become negative and Laughlin liquids are unstable for filling factors being less and equal to 1/7. We then conclude that there are correlated Wigner crystals for filling factors being less and equal to 1/7.