Giant Electron-Electron Scattering in the Fermi-Liquid State ofNa0.7CoO2

Abstract

The in-plane resistivity rho and thermal conductivity kappa of single crystal Na0.7CoO2 were measured down to 40 mK. Verification of the Wiedemann-Franz law, kappa/T=L(0)/rho as T-->0, and observation of a T2 dependence of rho at low temperature establish the existence of a well-defined Fermi-liquid state. The measured value of coefficient A reveals enormous electron-electron scattering, characterized by the largest Kadowaki-Woods ratio A/gamma(2) encountered in any material. The rapid suppression of A with magnetic field suggests a possible proximity to a magnetic quantum critical point. We also speculate on the possible role of magnetic frustration and proximity to a Mott insulator.

Structural, microstructural, and transport properties of highly oriented LaNiO3 thin films deposited on SrTiO3 (100) single crystal

“…In Fig. 4, it is also shown that the ͑T͒ data of LNO-MW thin film, in the same temperature range, devi- ates from the T 3/2 behavior and seems to obey the expression 35, the ratio r KW close to a 0 indicates strong electron correlations, further suggesting that such electron-electron scattering can be related to the proximity of a nearby Mott transition.…”

Transport properties and magnetic-field-induced localization in the misfit cobaltite [Bi2Ba1.3K0.6Co0.1O4]RS[CoO2]1.97single crystal

“…Such behavior is similar to that observed in Na 0.7 CoO 2 . [4] However, out-of-plane resistivity shows a weak semiconducting behavior below 12 K. Figure 2d indicates that the weak semiconducting behavior obeys thermal activation behavior with an activation energy of 0.013 meV. At high temperature, the out-of-plane resistivity shows metallic behavior up to room temperature.…”

Transport properties of the layered Rh oxide K0.49RhO2

“…This suggests that the electronic correlation in K 0.49 RhO 2 is weaker than that in Na x CoO 2 , although the T 2 law indicates significant correlation. Indeed, ρ of Na x CoO 2 is proportional to T 2 under the magnetic field [28], and we expect that the spin fluctuations are weaker in K 0.49 RhO 2 than in Na x CoO 2 , because the magnetic field suppresses the spin fluctuations.…”