Pseudo-zero-mode Landau levels and pseudospin waves in bilayer graphene

TL;DR

This paper investigates the properties of pseudo-zero-mode Landau levels in bilayer graphene under magnetic and electric fields, revealing collective excitations called pseudospin waves with potential experimental signatures.

Contribution

It provides a detailed analysis of the orbital mixing and collective excitations of pseudo-zero-mode levels in bilayer graphene, highlighting controllable pseudospin wave phenomena.

Findings

Pseudo-zero-mode levels support charge carriers with electric dipole moments.

Orbital mixing leads to collective pseudospin wave excitations.

Possible experimental signals of these excitations are discussed.

Abstract

Bilayer graphene in a magnetic field supports eight zero-energy Landau levels, which, as a tunable band gap develops, evolve into two nearly-degenerate quartets separated by the band gap. A close look is made into the properties of such an isolated quartet of pseudo-zero-mode levels at half filling in the presence of an in-plane electric field and the Coulomb interaction. The pseudo-zero-mode levels turn out to support, via orbital mixing, charge carriers with induced electric dipole moment, which lead to characteristic collective excitations, pseudospin waves, with some controllable features; possible experimental signals are discussed.