Determination of the gate-tunable band gap and tight-binding parameters in bilayer graphene using infrared spectroscopy

A. B. Kuzmenko, I. Crassee, D. van der Marel, P. Blake, K. S. Novoselov
2009 Physical Review B  
We present a compelling evidence for the opening of a bandgap in exfoliated bottom-gated bilayer graphene by fitting the gate-voltage modulated infrared reflectivity spectra in a large range of doping levels with a tight-binding model and the Kubo formula. A close quantitative agreement between the experimental and calculated spectra is achieved, allowing us to determine self-consistently the full set of Slonczewski-Weiss-McClure tight-binding parameters together with the gate-voltage dependent
more » ... bandgap. The doping dependence of the bandgap shows a good agreement with the existing calculations that take the effects of self-screening into account. We also identify certain mismatches between the tight-binding model and the data, which can be related to electron-electron and electron-phonon interactions.
doi:10.1103/physrevb.80.165406 fatcat:qmsmw4mlb5gx5iq3gkoofx3dke