Issue
EPL
Volume 88, Number 1, October 2009
Article Number 17011
Number of page(s) 6
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/88/17011
Published online 27 October 2009
EPL, 88 (2009) 17011
DOI: 10.1209/0295-5075/88/17011

Magnetically confined states of Dirac electrons in a graphene-based quantum annulus

Dali Wang and Guojun Jin

National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University Nanjing, 210093, China

gjin@nju.edu.cn

received 29 May 2009; accepted in final form 30 September 2009; published October 2009
published online 27 October 2009

Abstract
We propose to confine massless Dirac fermions in a graphene-based quantum annulus induced by an inhomogeneous magnetic field. It is found that influenced by an effective magnetic potential well the degeneracies of the relativistic Landau levels can be lifted, and the angular-momentum transitions in the ground state can occur by adjusting the geometry of the annulus and/or the magnitude of the magnetic field. Especially for high magnetic fields the system can form the strongly localized states in the annulus and around its boundaries, and some energy levels can reconverge to the Landau levels. Moreover, it is predicted that the dipole-allowed optical transitions between the low-lying energy levels can be measured by far-infrared spectroscopy, and the optical spectrum consists of a series of unequally spaced peaks.

PACS
73.21.-b - Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems.
75.70.Ak - Magnetic properties of monolayers and thin films.
81.05.Uw - Carbon, diamond, graphite.

© EPLA 2009