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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-4053
DTSTART:20160211T160000Z
DTEND:20160211T170000Z
DTSTAMP:20260425T135936Z
LAST-MODIFIED:20160128T132259Z
LOCATION:5310 Chamberlin Hall
SUMMARY:Origin of the in-plane resistivity anisotropy of the iron pnic
 tides: scattering rate or plasma frequency?\, R. G. Herb Condensed Mat
 ter Seminar\, Michael Schuett\, University of Minnesota
DESCRIPTION:In-plane resistivity anisotropy has been the prime tool to
  probe the electronic nematic state of the iron-based high-temperature
  superconductors. In these correlated phases\, the electronic degrees 
 of freedom spontaneously lower the point-group symmetry of the system 
 from tetragonal to orthorhombic. Thus\, the elucidation of the origin 
 of the resistivity anisotropy could provide invaluable information abo
 ut the microscopic nature of the nematic state of the iron pnictides. 
 In general\, an anisotropic resistivity anisotropy can be the result o
 f an anisotropic scattering rate (either elastic or inelastic) and/or 
 an anisotropic plasma frequency. To shed light on this problem\, here 
 we investigate the impact of spin fluctuations on the anisotropic ac c
 onductivity of the iron pnictides.<br>
\n<br>
\nWe show that spin fluc
 tuations affect both the scattering rate and the effective plasma freq
 uency. Interestingly\, the anisotropy in the effective scattering rate
  is antagonistic to the anisotropy induced in the effective plasma fre
 quency and can become comparable near the nematic transition temperatu
 re. As a result\, the ac conductivity may seem to be dominated by an e
 ffective plasma frequency anisotropy\, although the dc conductivity is
  actually determined solely by the scattering rate anisotropy. Our res
 ults agree qualitatively with recent experiments in detwinned iron pni
 ctides\, and reveal an unavoidable entanglement between scattering rat
 e anisotropy and plasma frequency anisotropy caused by spin fluctuatio
 ns.
URL:https://www.physics.wisc.edu/events/?id=4053
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