Plamadeala, Eugeniu and Pereg-Barnea, T. and Refael, Gil (2010) Probing order parameter structure in iron-based superconductors using vortices. Physical Review B, 81 (13). Art. No. 134513 . ISSN 1098-0121 http://resolver.caltech.edu/CaltechAUTHORS:20100525-143325995
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Impurities, inevitably present in all samples, induce elastic transitions between quasiparticle states on the contours of constant energy. These transitions may be seen in Fourier-transformed scanning tunneling spectroscopy experiments, sorted by their momentum transfer. In a superconductor, anomalous scattering in the pairing channel may be introduced by magnetic field. When a magnetic field is applied, vortices act as additional sources of scattering. These additional transitions may enhance or suppress the impurity-induced scattering. We find that the vortex contribution to the transitions is sensitive to the momentum-space structure of the pairing function. In the iron-based superconductors, there are both electron and hole pockets at different regions of the Brillouin zone. Scattering processes therefore represent intrapocket or interpocket transitions, depending on the momentum transfer in the process. In this work we show that while in a simple s-wave superconductor all transitions are enhanced by vortex scattering, in an s_± superconductor only intrapocket transitions are affected. We suggest this effect as a probe for the existence of the sign change in the order parameter.
|Additional Information:||© 2010 The American Physical Society. Received 2 December 2009; revised manuscript received 13 March 2010; published 13 April 2010. The authors would like to acknowledge useful discussions with M. Franz, O. Motrunich, and Z. Tešanović, the hospitality of the Aspen Center for Physics where some of the work has taken place, and funding from the Caltech SURF program (E.P.); the Packard and Sloan Foundations, the Institute for Quantum Information under NSF Grants No. PHY- 0456720 and No. PHY-0803371, and the Research Corporation Cottrell Scholars program (G.R.).|
|Classification Code:||PACS: 74.20.Rp, 74.25.Jb, 74.70.-b|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||01 Jun 2010 03:27|
|Last Modified:||26 Dec 2012 12:04|
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