Theory of two-particle excitations and the magnetic susceptibility in high-T_c cuprate superconductors

¹  Institute for Theoretical Physics and Astrophysics, University of Würzburg - Am Hubland, 97074 Würzburg, Germany, EU
²  Institute of Theoretical Physics and Computational Physics, Graz University of Technology - Petersgasse 16, 8010 Graz, Austria, EU
³  Centre de Physique Théorique, École Polytechnique - 91128 Palaiseau Cedex, France, EU

Corresponding author: arrigoni@tugraz.at

Abstract

Two-particle (2-p) excitations such as spin and charge excitations play a key role in high-T_c cuprate superconductors (HTSC). On the basis of a parameter-free theory, which extends the variational cluster approach (a recently developed embedded cluster method) to 2-p excitations, the magnetic excitations of HTSC are shown to be reproduced for a Hubbard model within the relevant strong-coupling regime. In particular, the resonance mode in the underdoped regime, its intensity and “hour-glass” dispersion are in good overall agreement with experiments.