QED3 Phase Diagram
Nernst Effect in HTS
Courtesy of N.P. Ong Vortex fluctuations in the pseudogap state !!
BiSrCaCuO
Z. A. Xu et al., Nature 406, 486 (2000)
HTS are Nodal d-wave Superconductors (Phase sensitive exps., ARPES, FT-STS, etc.)
Tsuei & Kirtley, 1997
FT-STS measured D
a
1.0
0.8
ky ( /a)
0.6
0.4
ARPES D(q), Mesot -PRL 83,840 (1999)
0.2 0.0 FT-STS from 0.0 0.2 Davis’ group, Nature 422, 520 (2003).
0.4
0.6
0.8
1.0
kx ( /a)
Courtesy of J.C. Davis
“Electron Crystal” in Underdoped Cuprates
M. Vershinin et al., Science 303, 1995 (2004); T. Hanaguri, C. Lupien et al., Nature 430, 1001 (2004)
Underdoped Ca2-xNaxCuO2Cl2 x=0.08 (I), 0.10 (SC), 0.12 (SC) Courtesy of J.C. Davis
Pseudogap State
Courtesy of A. Yazdani
K-Space
100K
Modulation along the Cu-O bond direction
150 pS
500Å x 200 Å
Cu-O
35 pS
Vershinin et al. Science 303, 1995 (2004)
Hofstadter Butterfly and Cooper Pair Density Wave in HTS
“Electron Crystal” in HTS (Vershinin, et al., Hanaguri, Lupien, et al.)
Hofstadter “Butterfly” Spectrum
Dual theory supplies the connection between two phenomena. It leads to Hofstadter “magic fractions” f = p/q for Cooper pair CDW at special x: f = p/q = (1-x)/2 !!