Topological polarization in graphene-like systems
de Nittis G, Lein M (2013)
Publication Status: Published
Publication Type: Journal article, Original article
Publication year: 2013
Journal
Publisher: Institute of Physics: Hybrid Open Access
Book Volume: 46
Article Number: 385001
Journal Issue: 38
DOI: 10.1088/1751-8113/46/38/385001
Abstract
In this paper we investigate the possibility of generating piezoelectric orbital polarization in graphene-like systems which are deformed periodically. We start with discrete two-band models which depend on control parameters; in this setting, time-dependent model Hamiltonians are described by loops in parameter space. Then, the gap structure at a given Fermi energy generates a non-trivial topology on parameter space which then leads to possibly non-trivial polarizations. More precisely, we show the polarization, as given by the King-Smith-Vanderbilt formula, depends only on the homotopy class of the loop; hence, a necessary condition for non-trivial piezo effects is that the fundamental group of the gapped parameter space must not be trivial. The use of the framework of non-commutative geometry implies that our results extend to systems with weak disorder. We then apply this analysis to the uniaxial strain model for graphene which includes nearest-neighbor hopping and a stagger potential, and show that it supports non-trivial piezo effects; this is in agreement with recent physics literature. © 2013 IOP Publishing Ltd.
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APA:
de Nittis, G., & Lein, M. (2013). Topological polarization in graphene-like systems. Journal of Physics A: Mathematical and Theoretical, 46(38). https://dx.doi.org/10.1088/1751-8113/46/38/385001
MLA:
de Nittis, Giuseppe, and Max Lein. "Topological polarization in graphene-like systems." Journal of Physics A: Mathematical and Theoretical 46.38 (2013).
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