Strong Correlations Produce the Curie-Weiss Phase of Na${}_x$CoO${}_2$

Abstract

Within the t-J model we study several experimentally accessible properties of the 2D-triangular lattice system Na${}_x$CoO${}_2$, using a numerically exact canonical ensemble study of 12 to 18 site triangular toroidal clusters as well as the icosahedron. Focusing on the doping regime of $x\sim 0.7$, we study the temperature dependent chemical potential, specific heat, magnetic susceptibility and the dynamic Hall coefficient $R_H(T,\omega )$ as well as the magnetic field dependent thermopower. We find a crossover between two phases near $x\sim 0.75$ in susceptibility and field suppression of the thermopower arising from strong correlations. An interesting connection is found between the temperature dependence of the diamagnetic susceptibility and the Hall-coefficient. We predict a large thermopower enhancement, arising from {\em transport corrections} to the Heikes-Mott formula, in a model situation where the sign of hopping is reversed from that applicable to Na${}_x$CoO${}_2$.

5 pages, 4 figures

References in corpus (2)

• Fermi surface and quasiparticle dynamics of Na(x)CoO2 {x=0.7} investigated by Angle-Resolved Photoemission Spectroscopy
• Fermi surface evolution and Luttinger theorem in Na${}_x$CoO${}_2$: a systematic photoemission study

Cited by in corpus (8)

• Thermoelectric effects in a strongly correlated model for Na${}_x$CoO${}_2$
• Magnetoresistance scaling in the layered cobaltate Ca3Co4O9
• Itinerant and localized magnetism on the triangular lattice: sodium rich phases of Na${}_x$CoO${}_2$
• Electron-phonon interaction in the lamellar cobaltate Na${}_x$CoO${}_2$
• Metal-nonmetal transition in LixCoO2 thin film and thermopower enhancement at high Li concentration
• Hall effect on the triangular lattice
• Tuning Kinetic Magnetism of Strongly Correlated Electrons via Staggered Flux
• Evidence for Oxygen Holes due to d-p Rehybridization in Thermoelectric Sr_{1-x}Rh_{2}O_{4}