Condensed-Matter Physics & Materials Science Seminar

High Tc Cuprates – still challenging theory after 20 years

T. M. Rice, ETH Zurich Switzerland

Although it is more than 20 years since the discovery of high temperature superconductivity, the cuprates continue to produce new and surprising results which challenge the goal of achieving a consistent theoretical understanding of all aspects of this fascinating field. This talk will concentrate on two recent developments. The first concerns the way in which Landau theory breaks down as the hole density is reduced in the overdoped region of the phase diagram. Recent functional RG calculations (1) show anisotropic scattering which grows with decreasing density and decreasing energy scale giving rise to an anisotropic inelastic scattering rate which is linear in temperature in qualitative agreement with recent transport studies by Hussey and collaborators.
A second set of calculations (2) inspired by the transport measurements of Li et al on the stripe phase, examines the energetics of anti-phase superconductivity in the presence of SDW and CDW order. Antiphase domain walls in a superconductor normally are energetically very expensive but our mean field results show a synergy between SDW and superconductivity which greatly reduces this cost. Our results however still give a small positive energy cost and leave open the origin of the final energy reduction needed to stablize antiphase superconductity.

1. M.Ossadnik et al cond-mat 0805.3489
2. K.Y. Yang et al (in preparation)