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arXiv · 1101.0971

Extended Ginzburg-Landau formalism for two-band superconductors

A. A. Shanenko·M. V. Milošević·F. M. Peeters·A. V. Vagov
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Abstract

Recent observation of unusual vortex patterns in MgB_2 single crystals raised speculations about a new type of superconductivity (named "type-1.5"). However, the strict application of the standard two-band Ginzburg-Landau (GL) theory results in simply proportional order parameters of the two bands - and does not support the "type-1.5" behavior. Here we derive the extended GL formalism (accounting all terms of the next order over the small t= 1- T/T_c parameter) for a two-band clean s-wave superconductor and show that the two condensates generally have different spatial scales, with difference disappearing only in the limit T -> T_c. The extended version of the two-band GL formalism improves the validity of GL theory below T_c, and suggests revisiting of the earlier calculations based on the standard model.

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A. A. Shanenko, M. V. Milošević, F. M. Peeters, A. V. Vagov. 2011-02-01. Extended Ginzburg-Landau formalism for two-band superconductors. https://doi.org/10.1103/physrevlett.106.047005

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