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SUMMARY:Superconductivity in underdoped cuprates from attraction between s
 pin vortices - Prof. Lu Yu (Institute of Physics\, Chinese Academy of Scie
 nces)
DTSTART:20091030T143000Z
DTEND:20091030T153000Z
UID:TALK21116@talks.cam.ac.uk
CONTACT:Joe Bhaseen
DESCRIPTION:The spin-charge gauge approach to the two-dimensional t-J mode
 l to consider the metal-insulator crossover and other anomalous transport 
 properties in High-Tc cuprates is first briefly reviewed. Within this fram
 ework we propose a new non-BCS mechanism for superconductivity in underdop
 ed cuprates. The gluing force is an attraction between spin vortices cente
 red at the empty sites (described by fermionic holons) in two different N
 éel sublattices. This attraction induces in turn\, through a gauge intera
 ction originated from the no-double occupation constraint\, formation of R
 esonance Valent Bond (RVB) spin pairs (described in terms of bosonic spino
 ns). When holon pairs condense\, a finite density of RVB spinon pairs appe
 ars. Superconductivity occurs at T=0 at a finite doping concentration\, wh
 en both holon- vortex pairs and the RVB spinon pairs are condensed. Its pr
 ecursor is a normal state region where magnetic vortices proliferate\, lea
 ding to superconductivity via a 3D gauged-XY transition.\n\nReferences:\n\
 n[1] P.A. Marchetti\, Z.B. Su\, L.Yu\, J. Phys. Condens. Matter 19\, 12520
 9 (2007) and references therein\n\n[2] P.A. Marchetti\, F. Ye\, Z.B. Su\, 
 L.Yu\, Proceedings of the 2009 M2S Conference\, September 2009\, Tokyo.\n
LOCATION:TCM Seminar Room\, Cavendish Laboratory
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