Cooper pair and spin fluctuations in underdoped high-temperature superconductors

¹ Universität Tübingen, Institut für Theoretische Physik Auf der Morgenstelle 14, 72076 Tübingen, Germany
² Freie Universität Berlin, Institut für Theoretische Physik Arnimallee 14, 14195 Berlin, Germany
³ Universität Hamburg, I. Institut für Theoretische Physik Jungiusstr. 9, 20355 Hamburg, Germany

Received: 16 October 2000
Accepted: 19 April 2001

Abstract

We have calculated the quasiparticle self-energy , spectral function , and density of states due to exchange of spin and d-wave pair fluctuations above in the FLEX (fluctuation exchange) approximation. We find that for a pseudogap evolves in which is similar to the structure caused by the superconducting d-wave gap below . A satellite peak occurs in for near which is caused by a peak in . Since these effects become relatively weak at higher temperatures , however, we have to conclude that fluctuations of the pair amplitude within this spin fluctuation pairing scenario cannot explain the observed pseudogap behavior well above in underdoped cuprates.