Dimensional crossover in Sr2RuO4 within a slave-boson mean-field theoryM. H. Fischer and M. Sigrist
Institute for Theoretical Physics, ETH Zürich - CH-8093 Zürich
received 28 August 2008; accepted in final form 5 January 2009; published January 2009
published online 30 January 2009
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.
71.27.+a - Strongly correlated electron systems; heavy fermions.
71.10.Pm - Fermions in reduced dimensions (anyons, composite fermions, Luttinger liquid, etc.).
71.10.Fd - Lattice fermion models (Hubbard model, etc.).
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