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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-1039
DTSTART:20080222T220000Z
DURATION:PT1H0M0S
DTSTAMP:20260423T055214Z
LAST-MODIFIED:19700101T060000Z
LOCATION:2241 Chamberlin Hall (coffee at 3:30 pm)
SUMMARY:Visualizing Pair Formation and the Riddle of High-Temperature 
 Superconductivity\, Physics Department Colloquium\, Ali Yazdani\, Prin
 ceton University
DESCRIPTION:The pairing of electrons underlies the formation of a supe
 rconducting state with zero electrical resistance. After twenty years 
 of work\, the mechanism of pairing and the temperature at which pairs 
 first form in high-temperature copper-oxide superconductors are still 
 hotly debated. Do pairs form at the critical temperature like conventi
 onal superconductors? Is pairing mediated by a bosonic excitation\, as
  in conventional BCS superconductors\, or is pairing with d-wave symme
 try an unavoidable consequence of strong Coulomb repulsion in these co
 mpounds?  In search of experimental answers to these important questio
 ns\, we have develop several new techniques\, based on the scanning tu
 nneling microscope (STM)\, to visualize the process of pair formation 
 on the atomic scale and to probe what controls the strength of pairing
  in these compounds with high precision. We show that pairing in the c
 uprates is strongly local\, with pairs forming in nanoscale regions of
  samples over a range of temperatures above the critical temperature. 
 I will discuss these experiments and other high resolution studies of 
 electronic states in search of clues as to what controls the strength 
 of the pairing interaction in the cuprates.  
URL:https://www.physics.wisc.edu/events/?id=1039
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