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SUMMARY:Nonreciprocal superconducting critical currents with normal state 
 field trainability in kagome superconductor CsV3Sb5
DTSTART;VALUE=DATE-TIME:20260612T020000Z
DTEND;VALUE=DATE-TIME:20260612T030000Z
DTSTAMP;VALUE=DATE-TIME:20260702T080800Z
UID:indico-event-5099@indico-tdli.sjtu.edu.cn
DESCRIPTION:Speakers: Jun Ge（葛君） (Peking University)\n\nHost: Pro
 f. Haibiao Zhou  Venue: TDLI Meeting Room N400Tencent Meeting link: htt
 ps://meeting.tencent.com/dm/9Ol2YzWipAvDMeeting ID: 446572423\, no passwor
 d Abstract:Determining time-reversal symmetry (TRS) and chirality in the 
 superconducting state and its relation to the symmetry and topology in the
  normal state are important issues in modern condensed matter physics. In 
 this talk\, I will introduce our observation of nonreciprocal superconduct
 ing critical currents (Ic) at zero applied magnetic field: Ic exhibits dif
 ferent values in opposite directions\, in both flakes and micro-bridges of
  the kagome superconductor CsV3Sb5. Such spontaneous nonreciprocity requir
 es TRS and inversion symmetry breakings. We find that the direction of asy
 mmetry changes randomly in repeated sample heating to 300 K and cooling in
 to the zero-resistance state\, consistent with the expected behavior arisi
 ng from spontaneous TRS breaking. Crucially\, on applying a perpendicular 
 magnetic field at 300 K\, above the charge density wave (CDW) transition a
 t TCDW in this compound and removing it to zero above the superconducting 
 onset critical temperature (Tc)\, the direction of the Ic asymmetry consis
 tently flips on changing the direction of the field. This magnetic field t
 raining ascertains that the CDW state above the superconducting transition
  temperature may also break the Z2 TRS and has a macroscopic directionalit
 y which can be changed by a uniform training field. The symmetry breaking 
 continues into the superconducting state and gives rise to the nonreciproc
 al superconducting critical currents. These results indicate the loop-curr
 ent CDW normal state with topological features in CsV3Sb5. Our observation
 s provide direct evidence for the TRS breaking in kagome superconductor Cs
 V3Sb5\, and offer new insights into the mechanism of TRS breaking in kagom
 e superconductors.  Biography:Dr. Jun Ge is currently a postdoctoral res
 earcher in Prof. Jian Wang’s group at department of Physics\, Peking Uni
 versity. She received her B.S. from Beijing Institute of Technology in 201
 7 and her Ph.D. in physics from Peking University in 2022. After her docto
 ral studies\, she continued as a postdoctoral researcher in Prof. Jian Wan
 g’s group. Her main research interest focuses on the quantum transport p
 roperties of low-dimensional superconductors and topological materials.\n\
 nhttps://indico-tdli.sjtu.edu.cn/event/5099/
LOCATION:Tsung-Dao Lee Institute/N4F-N400 - meeting room (Tsung-Dao Lee In
 stitute)
URL:https://indico-tdli.sjtu.edu.cn/event/5099/
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