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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-2301
DTSTART:20111006T150000Z
DURATION:PT1H0M0S
DTSTAMP:20260420T152625Z
LAST-MODIFIED:20111005T162659Z
LOCATION:5310 Chamberlin
SUMMARY:Superconducting gap symmetry in novel superconductors: insight
 s from quasiparticle interference\, R. G. Herb Condensed Matter Semina
 r\, Ilya Eremin\, Ruhr-University Bochum\, Germany
DESCRIPTION:Coherence factors are a hallmark of superconductivity as a
  pair-condensation phenomenon. When electrons pair\, quasi-particles d
 evelop an acute phase sensitivity to different types of scattering pot
 ential\, described by the appearance of coherence factors in the scatt
 ering amplitudes. While the  effects of phase-sensitive coherence fact
 ors are well established in isotropic superconductors\, they are much 
 harder to detect in their anisotropic counterparts\, such as high-Tc c
 uprates\, iron-based superconductors\, or heavy-fermion superconductor
 s. One of the recently developed technique to determine the phase stru
 cture of the superconducting order parameter is scanning tunneling mic
 roscopy (STM) which determines the dispersion of quasiparticle states 
 from the quasiparticle interference (QPI) patterns  induced by impurit
 y scattering. Such experiments\, performed in an external magnetic fie
 ld\, offer the capability of probing the phase of the superconducting 
 order parameter by detecting a field enhancement of the sign preservin
 g scattering that results from the sensitivity of QPI to the coherence
  factors associated with impurity scattering. In my talk I will review
  the experimental and theoretical results for layered cuprates and pre
 sent calculations of the QPI patterns in iron-based superconductors an
 d heavy fermion superconductor\, CeCoIn5 where the symmetries of the s
 uperconducting gaps are still actively debated. 
URL:https://www.physics.wisc.edu/events/?id=2301
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