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Friedel Oscillation-Induced Energy Gap Manifested as Transport Asymmetry at Monolayer-Bilayer Graphene Boundaries

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journal contribution
posted on 01.02.2014, 00:00 by Kendal W. Clark, X.-G. Zhang, Gong Gu, Jewook Park, Guowei He, Randall Feenstra, An-Ping Li

We show that Friedel charge oscillation near an interface opens a gap at the Fermi energy for electrons with wave vectors perpendicular to the interface. If the Friedel gaps on two sides of the interface are different, a nonequilibrium effect—shifting of these gaps under bias—leads to asymmetric transport upon reversing the bias polarity. The predicted transport asymmetry is revealed by scanning tunneling potentiometry at monolayer-bilayer interfaces in epitaxial graphene on SiC(0001). This intriguing interfacial transport behavior opens a new avenue toward novel quantum functions such as quantum switching.


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Published by the American Physical Society



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