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arXiv · 1309.2914

Accurate determination of electron-hole asymmetry and next-nearest neighbor hopping in graphene

A. Kretinin·G. L. Yu·R. Jalil·Y. Cao·F. Withers·A. Mishchenko·M. I. Katsnelson·K. S. Novoselov·A. K. Geim·F. Guinea
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Abstract

The next-nearest neighbor hopping term t' determines a magnitude and, hence, importance of several phenomena in graphene, which include self-doping due to broken bonds and the Klein tunneling that in the presence of t' is no longer perfect. Theoretical estimates for t' vary widely whereas a few existing measurements by using polarization resolved magneto-spectroscopy have found surprisingly large t', close or even exceeding highest theoretical values. Here we report dedicated measurements of the density of states in graphene by using high-quality capacitance devices. The density of states exhibits a pronounced electron-hole asymmetry that increases linearly with energy. This behavior yields t' approx -0.30 eV +-15%, in agreement with the high end of theory estimates. We discuss the role of electron-electron interactions in determining t' and overview phenomena which can be influenced by such a large value of t'.

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A. Kretinin, G. L. Yu, R. Jalil, Y. Cao, F. Withers, A. Mishchenko, M. I. Katsnelson, K. S. Novoselov, A. K. Geim, F. Guinea. 2013-09-15. Accurate determination of electron-hole asymmetry and next-nearest neighbor hopping in graphene. https://doi.org/10.1103/physrevb.88.165427

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