Effects of transverse electric fields on Landau subbands in bilayer zigzag graphene nanoribbons

TL;DR

This paper studies how transverse electric fields influence Landau subbands in bilayer zigzag graphene nanoribbons, revealing spectrum distortions, band mixing, and semiconductor-metal transitions through a tight-binding model.

Contribution

It introduces the effects of transverse electric fields on Landau subbands in bilayer zigzag graphene nanoribbons, highlighting spectrum tilting, band mixing, and phase transitions.

Findings

Electric fields distort energy spectra and tilt Landau subbands.

Band mixing phenomena are observed in the energy spectrum.

Electric fields induce semiconductor-metal transitions.

Abstract

The magnetoelectronic properties of quasi-one-dimensional zigzag graphene nanoribbons are investigated by using the Peierls tight-binding model. Quasi-Landau levels (QLLs), dispersionless Landau subbands within a certain region of k-space, are resulted from the competition between magnetic and quantum confinement effects. In bilayer system, the interlayer interactions lead to two groups of QLLs, one occurring at the Fermi level and the other one occurring at higher energies. Transverse electric fields are able to distort energy spectrum, tilt two groups of QLLs and cause semiconductor-metal transition. From the perspective of wave functions, the distribution of electrons is explored, and the evolution of Landau states under the influence of electric fields is clearly discussed. More interestingly, the band mixing phenomena exhibited in the energy spectrum are related to the state mixing, which can be apparently seen in the wave functions. The density of states, which could be verified through surface inspections and optical experiments, such as scanning tunneling spectroscopy and absorption spectroscopy, is provided at last.