Europhys. Lett.
Volume 72, Number 1, October 2005
Page(s) 117 - 123
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 26 August 2005
Europhys. Lett., 72 (1), pp. 117-123 (2005)
DOI: 10.1209/epl/i2005-10192-1

Weak phase separation and the pseudogap in the electron-doped cuprates

M. Aichhorn and E. Arrigoni

Institut für Theoretische Physik - Computational Physics, Technische Universität Graz Petersgasse 16, A-8010 Graz, Austria

received 12 May 2005; accepted in final form 27 July 2005
published online 26 August 2005

We study the quantum transition from an antiferromagnet to a superconductor in a model for electron- and hole-doped cuprates by means of a variational cluster perturbation theory approach. In both cases, our results suggest a tendency towards phase separation between a mixed antiferromagnetic-superconducting phase at low doping and a pure superconducting phase at larger doping. However, in the electron-doped case the energy scale for phase separation is an order of magnitude smaller than for hole doping. We argue that this can explain the different pseudogap and superconducting transition scales in hole- and electron-doped materials.

74.20.-z - Theories and models of superconducting state.
05.70.Jk - Critical point phenomena.
71.10.-w - Theories and models of many-electron systems.

© EDP Sciences 2005