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Parity and valley degeneracy in multilayer graphene

Research output: Contribution to journalJournal article

Published

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Journal publication date12/03/2010
JournalPhysical Review B
Journal number11
Volume81
Number of pages6
Original languageEnglish

Abstract

We study spatial symmetry in general ABA-stacked multilayer graphene to illustrate how electronic spectra at the two valleys are related in a magnetic field. We show that the lattice of multilayers with an even number of layers as well as that of monolayer graphene satisfy spatial inversion symmetry, which rigorously guarantees valley degeneracy in the absence of time-reversal symmetry. A multilayer with an odd number of layers (three or more) lacks inversion symmetry, but there is another transformation imposing an approximate valley degeneracy, which arises because the low-energy Hamiltonian consists of separate monolayerlike and bilayerlike parts. We show that an external electrostatic potential generally breaks valley degeneracy in a magnetic field, in a markedly different manner in odd and even multilayers.

Bibliographic note

© 2010 The American Physical Society