Band structure asymmetry of bilayer graphene revealed by infrared spectroscopy.
We report on infrared spectroscopy of bilayer graphene integrated in gated structures. We observe a significant asymmetry in the optical conductivity upon electrostatic doping of electrons and holes. We show that this finding arises from a marked asymmetry between the valence and conduction bands, which is mainly due to the inequivalence of the two sublattices within the graphene layer and the next-nearest-neighbor interlayer coupling. From the conductivity data, the energy difference of the two sublattices and the interlayer coupling energy are directly determined.
Li
Z Q
ZQ
Department of Physics, University of California, San Diego, La Jolla, California 92093, USA. zhiqiang@physics.ucsd.edu
Henriksen
E A
EA
Jiang
Z
Z
Hao
Z
Z
Martin
M C
MC
Kim
P
P
Stormer
H L
HL
Basov
D N
DN