Coherent incoherent pairing in 2D systems near magnetic instability
Department of Physics, University of Wisconsin - Madison, WI 53706, USA
2 Department of Codensed Matter Physics, Weizmann Institute of Science - Israel
Accepted: 28 February 2001
We study the superconductivity in 2D fermionic systems near antiferromagnetic instability, assuming that the pairing is mediated by spin fluctuations. This pairing involves fully incoherent fermions and diffusive spin excitations. We show that the competition between fermionic incoherence and strong pairing interaction yields the pairing instability temperature Tins which increases and saturates as the magnetic correlation length . We argue that in this quantum-critical regime the pairing problem is qualitatively different from the BCS one.
PACS: 71.10.Hf – Non-Fermi-liquid ground states, electron phase diagrams and phase transitions in model systems / 71.10.Li – Excited states and pairing interactions in model systems / 74.20.Mn – Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.)
© EDP Sciences, 2001