Dimensional crossover in Sr₂RuO₄ within a slave-boson mean-field theory

Institute for Theoretical Physics, ETH Zürich - CH-8093 Zürich

Corresponding author: mfischer@itp.phys.ethz.ch

Received: 28 August 2008
Accepted: 5 January 2009

Abstract

Motivated by the anomalous temperature dependence of the c-axis resistivity of Sr₂RuO₄, the dimensional crossover from a network of perpendicular one-dimensional chains to a two-dimensional system due to a weak hybridization between the perpendicular chains is studied. The corresponding two-orbital Hubbard model is treated within a slave-boson mean-field theory (SBMFT) to take correlation effects into account such as the spin-charge separation on the one-dimensional chains. Using an RPA-like formulation for the Green's function of collective spinon-holon excitations the emergence of quasiparticles at low-temperatures is examined. The results are used to discuss the evolution of the spectral density and the c-axis transport within a tunneling approach. For the latter a regime change between low- and high-temperature regime is found in qualitative accordance with experimental data.