Physica E 29 (2005) 469–474 Magneto-optical spectroscopy of carbon nanotubes S. Zaric a , G.N. Ostojic a , J. Shaver a , J. Kono a,Ã , X. Wei b , M. Furis c , S.A. Crooker c , O. Portugall d , P.H. Frings d , G.L.J.A. Rikken d , V.C. Moore e , R.H. Hauge e , R.E. Smalley e a Department of Electrical and Computer Engineering, Rice University, MS-366, 6100 Main St., Houston, TX 77005, USA b National High Magnetic Field Laboratory, 1800 E. Paul Dirac Drive, Tallahassee, FL 32310, USA c Optics and Laser Operations, National High Magnetic Field Laboratory, Mail Stop E536, Los Alamos, NM 87545, USA d Laboratoire National des Champs Magne´tiques Pulse´s, 143 Avenue de Rangueil—BP 14245, Toulouse Cedex 4 F-31432, France e Department of Chemistry, Rice University, P.O. Box 1892, MS-60, Houston, TX 77251, USA Available online 19 August 2005 Abstract We review our recent optical experiments on single-walled carbon nanotubes in high magnetic fields. The data revealed magnetic-field-induced optical anisotropy as well as broadening, splittings, and shifts of interband absorption and photoluminescence peaks. Quantitative comparison with theoretical predictions based on the Aharonov–Bohm effect is presented. r 2005 Elsevier B.V. All rights reserved. PACS: 73.22.f; 78.67.Ch; 75.75.+a Keywords: Carbon nanotubes; Aharonov–Bohm effect; Photoluminescence; Absorption; Magnetic alignment 1. Introduction The electronic structure of a single-walled carbon nanotube (SWNT) is influenced by a magnetic flux f threading the tube. This is due to the modification in the circumferential bound- ary condition introduced by the Aharonov–Bohm (AB) phase. As a result, the band gaps of both semiconducting and metallic nanotubes are pre- dicted [1,2] to oscillate as a function of a magnetic field with period f 0 ¼ e=h, i.e., magnetic flux quantum. For a standard SWNT with a diameter of 1nm, f ¼ f 0 is achieved in an external field of 6000 T applied parallel to the nanotube axis. There have been electronic transport experi- ments on multiwalled [3–6] as well as (relatively large-diameter) single-walled [7,8] carbon nano- tubes in magnetic fields. Although some of these ARTICLE IN PRESS www.elsevier.com/locate/physe 1386-9477/$-see front matter r 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.physe.2005.06.067 Ã Corresponding author. Tel.: +17133482209; fax: +17133485686. E-mail address: kono@rice.edu (J. Kono).