Volume 85, Number 5, March 2009
Article Number 57005
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 19 March 2009
EPL, 85 (2009) 57005
DOI: 10.1209/0295-5075/85/57005

Electric-field–induced lifting of the valley degeneracy in $\alpha$-(BEDT-TTF)2I3 Dirac-like Landau levels

M. O. Goerbig, J.-N. Fuchs, G. Montambaux and F. Piéchon

Laboratoire de Physique des Solides, CNRS UMR 8502, Université Paris-Sud - F-91405 Orsay Cedex, France, EU

received 12 January 2009; accepted in final form 13 February 2009; published March 2009
published online 19 March 2009

The relativistic Landau levels in the layered organic material $\alpha$-(BEDT-TTF)2I3 (BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene) are sensitive to the tilt of the Dirac cones, which, as in the case of graphene, determine the low-energy electronic properties under appropriate pressure. We show that an applied in-plane electric field, which happens to be in competition with the tilt of the cones, lifts the twofold valley degeneracy due to a different level spacing. This scenario may be tested in infrared transmission spectroscopy.

73.61.Wp - Fullerenes and related materials.
73.61.Ph - Polymers; organic compounds.
73.43.-f - Quantum Hall effects.

© EPLA 2009