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

Abstract

The magneto-electronic 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 -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 seen by 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.

Keywords:

• graphene nanoribbon
• electronic property
• magnetic property
• Landau level
• bilayer
• wave function

Acknowledgments

Hsien-Ching Chung thanks Ming-Hui Chung and Su-Ming Chen for their financial support.

Notes

This work was supported in part by the National Science Council of Taiwan [grant number 98-2112-M-006-013-MY4], and was supported in part by (received funding from) the Headquarters of University Advancement at the National Cheng Kung University, which is sponsored by the Ministry of Education, Taiwan.