Theory of the hourglass dispersion of magnetic excitations in high-Tc cuprates
Max-Planck-Institut für Festkörperforschung - Heisenbergstrasse 1, D-70569 Stuttgart, Germany, EU
Corresponding author: R.Zeyher@fkf.mpg.de
Accepted: 6 April 2010
A theory for the dispersion of collective magnetic excitations in superconducting cuprates is presented with the aim to cover both high- and low-doping regimes. Besides of spin fluctuations describable in the random phase approximation (RPA) we allow for local spin rotations within a mode-coupling theory. At low temperatures and moderately large correlation lengths we obtain two branches of excitations which disperse up- and downwards exhibiting the hourglass behavior observed experimentally at intermediate dopings. At large and small dopings our theory essentially reduces to the RPA and spin wave theory, respectively.
PACS: 75.40.Gb – Dynamic properties (dynamic susceptibility, spin waves, spin diffusion, dynamic scaling, etc.) / 74.25.Ha – Magnetic properties including vortex structures and related phenomena / 74.72.-h – Cuprate superconductors
© EPLA, 2010