Bose-Einstein condensation and Superfluidity of magnetoexcitons in Graphene

TL;DR

This paper proposes experiments to observe Bose-Einstein condensation and superfluidity of magnetoexcitons in bilayer graphene under strong magnetic fields, analyzing their spectra, superfluid density, and phase transition temperature.

Contribution

It introduces a theoretical framework for observing BEC and superfluidity of magnetoexcitons in bilayer graphene, including calculations of spectra and phase transition parameters.

Findings

Superfluid density increases with exciton density.

Transition temperature decreases with magnetic field and interlayer separation.

Numerical results support the feasibility of observing these phenomena.

Abstract

We propose experiments to observe Bose-Einstein condensation (BEC) and superfluidity of quasi-two-dimensional (2D) spatially indirect magnetoexcitons in bilayer graphene. The magnetic field $B$ is assumed strong. The energy spectrum of collective excitations, the sound spectrum as well as the effective magnetic mass of magnetoexcitons are presented in the strong magnetic field regime. The superfluid density $n_S$ and the temperature of the Kosterlitz-Thouless phase transition $T_c$ are shown to be increasing functions of the excitonic density $n$ but decreasing functions of $B$ and the interlayer separation $D$. Numerical results are presented from these calculations.