Effective actions and phase fluctuations in d-wave superconductors

Paramekanti, Arun and Randeria, Mohit and Ramakrishnan, TV and Mandal, SS (2000) Effective actions and phase fluctuations in d-wave superconductors. In: Physical Review B, 62 (10). pp. 6786-6789.

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Abstract

We study effective actions for order-parameter fluctuations at low temperature in layered d-wave superconductors such as the cuprates. The order parameter Lives on the bonds of a square lattice and has two amplitude and two phase modes associated with it. The low-frequency spectral weights for amplitude and relative phase fluctuations is determined and found to be subdominant to quasiparticle contributions. The Goldstone phase mode and its coupling to density fluctuations in;charged systems is treated in a gauge invariant manner. The Gaussian phase action is used to study both the c-axis Josephson plasmon and the more conventional in-plane plasmon in the cuprates. We go beyond the Gaussian theory by deriving a coarse-grained quantum XY model, which incorporates important cutoff effects overlooked in previous studies. A variational analysis of this effective model shows that in the cuprates, quantum effects of phase fluctuations are important in reducing the zero-temperature superfluid stiffness, but thermal effects are small for T<<T-c

Item Type:	Journal Article
Publication:	Physical Review B
Publisher:	American Physical Society
Additional Information:	Copyright of the article belongs to American Physical Society.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	02 Jun 2009 10:34
Last Modified:	19 Sep 2010 04:56
URI:	http://eprints.iisc.ac.in/id/eprint/17226

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