Gauge-theory approach to planar doped antiferromagnets and external magnetic fields

Farakos, K; Mavromatos, NE

dc.contributor.author	Farakos, K	en
dc.contributor.author	Mavromatos, NE	en
dc.date.accessioned	2014-03-01T01:13:46Z
dc.date.available	2014-03-01T01:13:46Z
dc.date.issued	1998	en
dc.identifier.issn	0217-9792	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/12712
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-0002532693&partnerID=40&md5=c7b58453532ec0f539a5c4994f879b0c	en
dc.subject.classification	Physics, Applied	en
dc.subject.classification	Physics, Condensed Matter	en
dc.subject.classification	Physics, Mathematical	en
dc.subject.other	DYNAMICAL SYMMETRY-BREAKING	en
dc.subject.other	2-DIMENSIONAL SUPERCONDUCTIVITY	en
dc.subject.other	QUANTUM ANTIFERROMAGNET	en
dc.subject.other	HIGH-TEMPERATURE	en
dc.subject.other	2+1 DIMENSIONS	en
dc.subject.other	LATTICE	en
dc.subject.other	FERMIONS	en
dc.subject.other	PARITY	en
dc.subject.other	ELECTRODYNAMICS	en
dc.subject.other	YBA2CU3O7-DELTA	en
dc.title	Gauge-theory approach to planar doped antiferromagnets and external magnetic fields	en
heal.type	journalArticle	en
heal.language	English	en
heal.publicationDate	1998	en
heal.abstract	Within the framework of a relativistic non-abelian gauge theory approach to the physics of spin-charge separation in doped quantum antiferromagnetic planar systems, proposed recently by the authors, we are examining here the effects of constant external magnetic fields on excitations about the superconducting state in the model. The electrically-charged Dirac fermions (holons), describing excitations about specific points on the fermi surface, e.g. those corresponding to the nodes of a d-wave superconducting gap in high-T-c cuprates, condense, resulting in the opening of a Kosterlitz-Thouless-like gap (KT) at such nodes. This leads, in general, to a second superconducting phase transition, which occurs at low temperatures (T-c similar to O(0.1) K), in addition to the high-T-c superconductivity (T-c similar to O(100) K) due to the bulk of the fermi surface for holons in a (d-wave) spin-charge separated superconductor. In the presence of strong external magnetic fields at the surface regions of the planar superconductor, in the direction perpendicular to the superconducting planes, these KT gaps appear to be enhanced. Our preliminary analysis, based on analytic Schwinger-Dyson treatments, seems to indicate that for an even number of Dirac fermion species, required in our model as a result of gauging a particle-hole SU(2) symmetry, Parity or Time Reversal violation does not necessarily occurs. Based on these considerations, we argue that recent experimental findings, concerning thermal conductivity plateaux of quasiparticles in planar high-T-c cuprates in strong external magnetic fields, may indicate the presence of such KT gaps, caused by charged Dirac-fermion excitations in these materials, as suggested in the above model.	en
heal.publisher	WORLD SCIENTIFIC PUBL CO PTE LTD	en
heal.journalName	International Journal of Modern Physics B	en
dc.identifier.isi	ISI:000073303800004	en
dc.identifier.volume	12	en
dc.identifier.issue	7-8	en
dc.identifier.spage	809	en
dc.identifier.epage	836	en