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DTSTART:20240331T030000
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DTSTAMP:20260425T051708Z
UID:1710237600@ist.ac.at
DTSTART:20240312T110000
DTEND:20240312T120000
DESCRIPTION:Speaker: Christian Ast\nhosted by Georgios Katsaros\nAbstract: 
 Magnetic impurities on superconductors give rise to discrete bound states 
 inside the superconducting gap known as Yu-Shiba-Rusinov (YSR) states. Var
 ying the impurity-superconductor coupling induces a quantum phase transiti
 on (QPT) as the YSR state energy passes through zero. The concomitant sign
  change in the Josephson current – a long sought for hallmark of this QP
 T – has remained elusive so far. Using scanning tunneling microscopy (ST
 M)\, we demonstrate such a 0 to  transition of a Josephson junction throug
 h a YSR state as we continuously change the impurity-superconductor coupli
 ng [1]. We detect the sign change in the Josephson current by exploiting a
  second transport channel as a reference in analogy to a superconducting q
 uantum interference device (SQUID)\, which provides a rudimentary phase se
 nsitivity for the STM. The change in the Josephson current through the QPT
  is significant and demonstrates the role of the impurity spin as well as 
 the parity change across the QPT.[1] Karan\, et al.\, Nature Physics 18\, 
 893 (2022)
LOCATION:Heinzel Seminar Room / Ground Floor / Office Building West\, ISTA
ORGANIZER:sandra.widdmann@ista.ac.at
SUMMARY:Christian Ast: Superconducting Quantum Interference at the Atomic S
 cale
URL:https://talks-calendar.ista.ac.at/events/4712
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