Tunable Luttinger liquid physics in biased bilayer graphene

TL;DR

This paper demonstrates that biased bilayer graphene with a spatially varying interlayer bias hosts one-dimensional chiral modes that behave as a tunable, strongly interacting Tomonaga-Luttinger liquid with unique velocities and interaction parameters.

Contribution

It introduces a model of 1D chiral modes in biased bilayer graphene and shows they exhibit tunable Luttinger liquid behavior influenced by gate voltage.

Findings

1D chiral modes are localized along the bias domain wall.

These modes exhibit strong interactions characterized by a bias-dependent Luttinger parameter.

The system displays three distinct mode velocities influenced by the bias.

Abstract

Electronically gated bilayer graphene behaves as a tunable gap semiconductor under a uniform interlayer bias $V_{g}$. Imposing a spatially varying bias, which changes polarity from $-V_g$ to $+V_g$, leads to one dimensional (1D) chiral modes localized along the domain wall of the bias. Due to the broad transverse spread of their low-energy wavefunctions, we find that the dominant interaction between these 1D electrons is the forward scattering part of the Coulomb repulsion. Incorporating these interactions and the gate voltage dependence of the dispersion and wavefunctions, we find that these 1D modes behave as a strongly interacting Tomonaga-Luttinger liquid with three distinct mode velocities and a bias dependent Luttinger parameter, and discuss its experimental signatures.