Tunable interactions and phase transitions in Dirac materials in a magnetic field

TL;DR

This paper explores how magnetic fields can tune electron interactions in Dirac materials, enabling control over various correlated phases and phase transitions within Landau levels, with implications for materials like graphene and topological insulators.

Contribution

It demonstrates a method to tune effective electron interactions in Dirac materials using magnetic fields, allowing in situ control of different quantum phases.

Findings

Different phases can be stabilized in a single Landau level.

Phase transitions can be driven in situ by magnetic field tuning.

Incompressible liquids with Abelian and non-Abelian properties are realized.

Abstract

A partially filled Landau level (LL) hosts a variety of correlated states of matter with unique properties. The ability to control these phases requires tuning the effective electron interactions within a LL, which has been difficult to achieve in GaAs-based structures. Here we consider a class of Dirac materials in which the chiral band structure, along with the mass term, gives rise to a wide tunability of the effective interactions by the magnetic field. This tunability is such that different phases can occur in a single LL, and phase transitions between them can be driven in situ. The incompressible, Abelian and non-Abelian, liquids are stabilized in interaction regimes different from GaAs. Our study points to a realistic method of controlling the correlated phases and studying the phase transitions between them in materials such as graphene, bilayer graphene, and topological insulators.