토토 승무패PHYSICS/BK21 SEMINAR[09.06.10 ]pm2:00~
관련링크
본문
"
“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)토토 승무패2:00토토 승무패~토토 승무패3:00 pm
Abstract
One possible explanation for the mysterious ‘pseudogap’ state of the hole-doped cuprate superconductors
is that it is a d-wave superconductor토토 승무패but토토 승무패without토토 승무패quantum토토 승무패phase토토 승무패rigidity.토토 승무패While토토 승무패several토토 승무패transport토토 승무패and
thermodynamic studies indicate this to be true for some regions of the phase토토 승무패diagram,토토 승무패unanimity토토 승무패on토토 승무패the
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.토토 승무패Thus,토토 승무패our토토 승무패data provide direct spectroscopic evidence for phase
incoherent superconductivity in the underdoped토토 승무패pseudogap토토 승무패regime토토 승무패and토토 승무패also토토 승무패a토토 승무패new토토 승무패perspective on the
temperature evolution of토토 승무패the토토 승무패superconducting토토 승무패energy토토 승무패gap.토토 승무패Moreover,토토 승무패they토토 승무패reveal토토 승무패that토토 승무패the토토 승무패pseudogap
electronic structure consists토토 승무패of토토 승무패three토토 승무패distinct토토 승무패elements:토토 승무패the토토 승무패Fermi arc,토토 승무패the토토 승무패gap토토 승무패to토토 승무패coherent토토 승무패k-space
excitations of a phase disordered d-wave superconductor, and the gap to non-dispersive locally symmetry
breaking excitations at the pseudogap energy scale.토토 승무패I 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 determine토토 승무패the토토 승무패Green’s토토 승무패function토토 승무패and토토 승무패the토토 승무패scattering토토 승무패matrix
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)
"
“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)토토 승무패2:00토토 승무패~토토 승무패3:00 pm
Abstract
One possible explanation for the mysterious ‘pseudogap’ state of the hole-doped cuprate superconductors
is that it is a d-wave superconductor토토 승무패but토토 승무패without토토 승무패quantum토토 승무패phase토토 승무패rigidity.토토 승무패While토토 승무패several토토 승무패transport토토 승무패and
thermodynamic studies indicate this to be true for some regions of the phase토토 승무패diagram,토토 승무패unanimity토토 승무패on토토 승무패the
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.토토 승무패Thus,토토 승무패our토토 승무패data provide direct spectroscopic evidence for phase
incoherent superconductivity in the underdoped토토 승무패pseudogap토토 승무패regime토토 승무패and토토 승무패also토토 승무패a토토 승무패new토토 승무패perspective on the
temperature evolution of토토 승무패the토토 승무패superconducting토토 승무패energy토토 승무패gap.토토 승무패Moreover,토토 승무패they토토 승무패reveal토토 승무패that토토 승무패the토토 승무패pseudogap
electronic structure consists토토 승무패of토토 승무패three토토 승무패distinct토토 승무패elements:토토 승무패the토토 승무패Fermi arc,토토 승무패the토토 승무패gap토토 승무패to토토 승무패coherent토토 승무패k-space
excitations of a phase disordered d-wave superconductor, and the gap to non-dispersive locally symmetry
breaking excitations at the pseudogap energy scale.토토 승무패I 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 determine토토 승무패the토토 승무패Green’s토토 승무패function토토 승무패and토토 승무패the토토 승무패scattering토토 승무패matrix
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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