Onset of Quantum Criticality in the Topological-to-Nematic Transition in a Two-dimensional Electron Gas at Filling Factor $\nu=5/2$

TL;DR

This study investigates the phase transition in a two-dimensional electron gas at filling factor 5/2 under pressure, revealing quantum criticality and contrasting electron-based and composite fermion descriptions.

Contribution

It provides the first detailed phase diagram of the fractional quantum Hall and stripe phases at ν=5/2 under pressure, highlighting quantum critical behavior.

Findings

Transition from fractional quantum Hall to stripe phase with pressure

Identification of quantum critical point in the phase diagram

Evidence for dual descriptions of the half-filled Landau level

Abstract

Under hydrostatic pressure, the ground state of a two-dimensional electron gas at $\nu=5/2$ changes from a fractional quantum Hall state to the stripe phase. By measuring the energy gap of the fractional quantum Hall state and of the onset temperature of the stripe phase we mapped out a phase diagram of these competing phases in the pressure-temperature plane. Our data highlight the dichotomy of two descriptions of the half-filled Landau level near the quantum critical point: one based on electrons and another on composite fermions.