Phases of the excitonic condensate in two-layer graphene

TL;DR

This paper investigates the different phases of excitonic condensates in a two-layer graphene system, considering symmetry effects, external magnetic fields, and carrier imbalance to map out the phase diagram.

Contribution

It introduces a comprehensive phase diagram for excitonic insulator states in two-layer graphene, accounting for valley, spin degeneracy, and external symmetry-breaking influences.

Findings

Identified symmetry-breaking effects due to magnetic field and carrier imbalance.

Mapped phase transitions between different excitonic states.

Provided insights into the conditions favoring various condensate phases.

Abstract

Two graphene monolayers that are oppositely charged and placed close to each other are considered. Taking into account valley and spin degeneracy of electrons we analyze the symmetry of the excitonic insulator states in such a system and build a phase diagram that takes into account the effect of the symmetry breaking due to the external in-plane magnetic field and the carrier density imbalance between the layers.