Superconducting states of the quasi-2D Holstein model: effects of vertex and non-local corrections

Hague, J. P. (2005). Superconducting states of the quasi-2D Holstein model: effects of vertex and non-local corrections. Journal of Physics: Condensed Matter, 17(37), pp. 5663–5676.

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DOI (Digital Object Identifier) Link:	http://dx.doi.org/doi:10.1088/0953-8984/17/37/005
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Abstract

I investigate superconducting states in a quasi-2D Holstein model using the dynamical cluster approximation. The effects of spatial fluctuations (non-local corrections) are examined and approximations neglecting and incorporating lowest order vertex corrections are computed. The approximation is expected to be valid for electron–phonon couplings of less than the bandwidth. The phase diagram and superconducting order parameter are calculated. Effects which can only be attributed to theories beyond Migdal–Eliashberg theory are present. In particular, the order parameter shows momentum dependence on the Fermi surface with a modulated form and s-wave order is suppressed at half-filling. The results are discussed in relation to Hohenberg's theorem and the Bardeen–Cooper–Schrieffer approximation.

Item Type:	Journal Article
ISSN:	0953-8984
Academic Unit/Department:	Science > Physical Sciences
Interdisciplinary Research Centre:	Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID:	12286
Depositing User:	James Hague
Date Deposited:	13 May 2009 14:25
Last Modified:	05 Dec 2010 06:19
URI:	http://oro.open.ac.uk/id/eprint/12286

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