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    “Spectroscopic Fingerprint of Phase Incoherent
       Superconductivity in the Pseudogap State of
                Underdoped Bi2Sr2CaCu2O8+δ”
  
♦Speaker : Dr. Jhinhwan Lee (Cornell University)
♦Place : Physics Seminar Room (Science Bldg, 3-201)
♦Date & Time : June, 10(Wed)검증 바카라2:00검증 바카라~검증 바카라3:00 pm

Abstract
  
One possible explanation for the mysterious ‘pseudogap’ state of the hole-doped cuprate superconductors
is that it is a d-wave superconductor검증 바카라but검증 바카라without검증 바카라quantum검증 바카라phase검증 바카라rigidity.검증 바카라While검증 바카라several검증 바카라transport검증 바카라and
thermodynamic studies indicate this to be true for some regions of the phase검증 바카라diagram,검증 바카라unanimity검증 바카라on검증 바카라the
extent of these regions is lacking. Thus the spectroscopic ‘fingerprint’ of phase incoherent superconductivity
would be invaluable to determine precisely where this state occurs. One spectroscopic signature of d-wave
superconductivity is the particle-hole symmetric ‘octet’ of dispersive Bogoliubov quasiparticle interference
(QPI) modulations. In this presentation I will report the temperature dependence of the complete QPI octet
from low temperatures to well into the pseudogap regime. Remarkably, we find no dramatic changes in the
QPI octet phenomenology at the superconductor’s critical temperature Tc and, indeed, show that it exists at
all temperatures up to at least T ~ 1.5Tc.검증 바카라Thus,검증 바카라our검증 바카라data provide direct spectroscopic evidence for phase
incoherent superconductivity in the underdoped검증 바카라pseudogap검증 바카라regime검증 바카라and검증 바카라also검증 바카라a검증 바카라new검증 바카라perspective on the
temperature evolution of검증 바카라the검증 바카라superconducting검증 바카라energy검증 바카라gap.검증 바카라Moreover,검증 바카라they검증 바카라reveal검증 바카라that검증 바카라the검증 바카라pseudogap
electronic structure consists검증 바카라of검증 바카라three검증 바카라distinct검증 바카라elements:검증 바카라the검증 바카라Fermi arc,검증 바카라the검증 바카라gap검증 바카라to검증 바카라coherent검증 바카라k-space
excitations of a phase disordered d-wave superconductor, and the gap to non-dispersive locally symmetry
breaking excitations at the pseudogap energy scale.검증 바카라I will also address in detail the technical challenges in
the high-precision variable-temperature QPI measurement and present a new cross-sectional QPI analysis
scheme that can be used to more accurately determine검증 바카라the검증 바카라Green’s검증 바카라function검증 바카라and검증 바카라the검증 바카라scattering검증 바카라matrix
elements. Together they will form the technological basis of mapping the Green’s function and the scattering
matrix elements over the entire phase diagram of an unknown material.

  
      Contact Person : Prof. Ki Bong Lee(054-279-2068, kibong@postech.ac.kr)


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