Phys. Rev. B 80, 153412 (2009) [4 pages]Merging of Dirac points in a two-dimensional crystalReceived 21 April 2009; published 27 October 2009 We study under which general conditions a pair of Dirac points in the electronic spectrum of a two-dimensional crystal may merge into a single one. The merging signals a topological transition between a semimetallic phase and a band insulator. We derive a universal Hamiltonian that describes the physical properties of the transition, which is controlled by a single parameter, and analyze the Landau-level spectrum in its vicinity. This merging may be observed in the organic salt α−(BEDT-TTF)2I3 or in an optical lattice of cold atoms simulating deformed graphene. © 2009 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevB.80.153412
DOI:
10.1103/PhysRevB.80.153412
PACS:
73.61.Wp, 73.61.Ph, 73.43.−f
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