Effects of edge potential on an armchair-graphene open boundary and nanoribbons

Chi Hsuan Chiu*, Chon-Saar Chu

*Corresponding author for this work

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Pseudospin flipping is found to be the key process leading to the formation of an edge-potential-induced edge state at an armchair-graphene open boundary and nanoribbons. At an open boundary, the edge potential U 0 is shown to turn on pseudospin-flipped (intravalley) scattering even though U 0 does not post an apparent breaking of the AB site (basis atoms) symmetry. For a valley-polarized incident beam, the interference between the pseudospin-conserving (intervalley) and -nonconserving (intravalley) processes in the scattering state leads to a finite out-of-plane pseudospin density. This two-wave feature in the evanescent regime leads to the formation of the edge state. The physical origin of the edge state is different from that for the Tamm states in semiconductors. For an armchair-graphene nanoribbon with a gapless energy spectrum, applying U 0 to both edges opens up an energy gap. Both edge states and energy gap opening exhibit distinct features in nanoribbon conductance.

Original languageEnglish
Article number155444
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume85
Issue number15
DOIs
StatePublished - 23 Apr 2012

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