Compressibility of Interacting Electrons in Bilayer Graphene

TL;DR

This paper investigates how electron interactions and an externally tunable energy gap affect the compressibility of electrons in bilayer graphene, revealing stability across different gap conditions.

Contribution

It applies the renormalized-ring-diagram approximation to analyze the impact of energy gaps on electron compressibility in bilayer graphene, a novel approach in this context.

Findings

Compressibility is linked to spin susceptibility.

Energy gaps significantly alter chemical potential and compressibility.

System remains stable for both zero and finite gaps.

Abstract

Using the renormalized-ring-diagram approximation, we study the compressibility of the interacting electrons in bilayer graphene. The compressibility is equivalent to the spin susceptibility apart from a constant factor. The chemical potential and the compressibility of the electrons can be significantly altered by an energy gap (tunable by external gate voltages) between the valence and conduction bands. For zero gap and a typical finite gap in the experiments, we show both systems are stable.