Eur. Phys. J. B 57, 271-278 (2007)
https://doi.org/10.1140/epjb/e2007-00179-2

Doping-dependent evolution of low-energy excitations and quantum phase transitions within an effective model for high-T_c copper oxides

¹ L.V. Kirensky Institute of Physics, Siberian Branch of Russian Academy of Sciences, 660036 Krasnoyarsk, Russia
² Max-Planck-Institut für Physik komplexer Systeme, 01187 Dresden, Germany

Corresponding author: ^a maxim@mpipks-dresden.mpg.de

Received: 20 March 2007
Revised: 21 May 2007
Published online: 22 June 2007

Abstract

In this paper a mean-field theory for the spin-liquid paramagnetic non-superconducting phase of the p- and n-type high-T_c cuprates is developed. This theory applied to the effective t-t'-t′′-J^* model with the ab initio calculated parameters and with the three-site correlated hoppings. The static spin-spin and kinematic correlation functions beyond Hubbard-I approximation are calculated self-consistently. The evolution of the Fermi surface and band dispersion is obtained for the wide range of doping concentrations x. For p-type systems the three different types of behavior are found and the transitions between these types are accompanied by the changes in the Fermi surface topology. Thus a quantum phase transitions take place at x = 0.15 and at x = 0.23.Due to the different Fermi surface topology we found for n-type cuprates only one quantum critical concentration, x = 0.2. The calculated doping dependence of the nodal Fermi velocity and the effective mass are in good agreement with the experimental data.