Universal conductivity and the electrodynamics of graphite at high pressures.

Perucchi, A;Baldassarre, L;Marini, C;Postorino, P;BERNARDINI, FABIO;MASSIDDA, SANDRO SALVATORE;Lupi, S.

2012-01-01

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Abstract

We address the in-plane pressure-dependent electrodynamics of graphite through synchrotron-based infrared spectroscopy and ab initio density functional theory calculations. The Drude term remarkably increases upon pressure application, as a consequence of an enhancement of both electron and hole charge densities. This is due to the growth of the band dispersion along the k(z) direction between the K and H points of the Brillouin zone. On the other hand, the mid-infrared optical conductivity between 800 and 5000 cm(-1) is almost flat, and very weakly pressure dependent, at least up to 7 GPa. This demonstrates a surprising robustness of the graphene-like universal quantum conductance of graphite, even when the interlayer distance is significantly reduced.