BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-1703
DTSTART:20100128T160000Z
DURATION:PT1H0M0S
DTSTAMP:20260422T131526Z
LAST-MODIFIED:20091208T214226Z
LOCATION:5310 Chamberlin
SUMMARY:Competition between superconductivity and magnetism in the iro
 n arsenides\, R. G. Herb Condensed Matter Seminar\, Rafael Fernandes\,
  Ames National Laboratory
DESCRIPTION:The new iron arsenide superconductors present a very rich 
 phase diagram\, displaying superconducting\, antiferromagnetic and str
 uctural order. In this seminar\, I present a microscopic theory to stu
 dy the interplay between electronic and magnetic degrees of freedom. I
 n this model\, electrons sharing the same bands are responsible for bo
 th superconductivity and itinerant magnetism\, causing these two state
 s to compete. Then\, two distinct outcomes are possible: either these 
 two states are mutually exclusive and phase separate or they can coexi
 st microscopically. Using a mean-field approach\, I analyze the relati
 onship between these two scenarios and the symmetry of the Cooper-pair
  wave function. In particular\, I show that while the so-called s<sup>
 ++</sup> state is generally incompatible to the antiferromagnetic phas
 e\, the unconventional s<sup>+-</sup> state is able to coexist with ma
 gnetism. Thus\, valuable information about the nature of the supercond
 ucting phase can be extracted directly from the phase diagrams of the 
 iron arsenides.
URL:https://www.physics.wisc.edu/events/?id=1703
END:VEVENT
END:VCALENDAR