Universal low Coherence Temperature in the one band Hubbard model: A slave-boson approach

MEZIO, ALEJANDRO; MCKENZIE, ROSS H.

Paris

Seminario; Seminario de Physique de la matière condensée; 2017

Collège de France

The metallic phase of a wide range of strongly correlated materials exhibit properties consistent with a Fermi liquid picture, but only below a low-temperature scale. At this coherence temperature Tcoh there is a crossover to a regime without quasiparticles and incoherent transport, i.e., a bad metallic state. In this work [1] we use the Kotliar-Ruckenstein slave-boson formalism to study the temperature dependence of paramagnetic phases of the one-band Hubbard model. We calculate the Fermi liquid quasiparticle spectral weight Z and identify the temperature at which it decreases significantly as a crossover to a bad metal region. Near the Mott metal-insulator transition, we find this Tcoh to be much lower than the Fermi temperature of the uncorrelated Fermi gas, as is observed in a broad range of materials. We obtain the temperature-correlation phase diagram as a function of doping. We find qualitative agreement for the temperature dependence of the double occupancy, entropy, and charge compressibility with previous results obtained with Dynamical Mean-Field Theory. We use the charge compressibility to analyse the stability of the technique.