Related papers: Spin fluctuations, magnetic long-range order and F…
We investigate the electronic states and the transport properties of the CoO2 plane in NaxCoO2 on the basis of the two-dimensional triangular lattice 11-band d-p model by using the fluctuation exchange approximation, where we consider the…
We analyze the normal electronic states of Na$_{0.35}$CoO$_2$ based on the multi-orbital Hubbard model using the FLEX approximation. The fundamental electronic property of this system is drastically changed by the presence or absence of the…
Zero field and longitudinal field muon spin relaxation measurements have been performed in optimally doped and overdoped superconductors LaFeAsO$_{1-x}$F$_x$ in order to investigate the magnetic fluctuation over a wide range of temperature…
We report Raman scattering experiments on the strongly correlated electron system NaxCoO2 with x= 0.71 and ordered Na vacancies. In this doping regime, NaxCoO2 exhibits a large and unusual thermopower and becomes superconducting upon…
We report a study of magnetic, thermal, and transport properties of La(3+) substituted Sr2RuO4, performed in order to investigate the effects of additional electron doping in this correlated metal. A gradual enhancement of the electronic…
The strength and effect of Coulomb correlations in the (superconducting when hydrated) x~1/3 and ``enhanced'' x~2/3 regimes of Na(x)CoO2 are evaluated using the correlated band theory LDA+U method. Our results, neglecting quantum…
Reduced dimensionality offers a crucial information in deciding the type of the quantum ground state in heavy fermion materials. Here we have examined stoichiometric CeCo$_{2}$Ga$_{8}$ compound, which crystallizes in a quasi-one-dimensional…
Motivated by recently reported experimental phase diagrams, we study the effects of CoO6 distortion on the electronic structure in NaxCoO2.yH2O. We construct the multiband tight-binding model by employing the LDA result. Analyzing this…
To elucidate the low-energy excitation spectrum of correlated electrons on a 2D triangular lattice, we have studied the electrical resistance and specific heat down to 0.5 K and in magnetic fields up to 14 T, in NaxCoO2 samples with a Na…
Density functional calculations are used to investigate the doping dependence of the electronic structure and magnetic properties in hexagonal Na$_x$CoO$_2$. The electronic structure is found to be highly two dimensional, even without…
Electronic properties of the sodium cobaltate NaxCoO2 are systematically studied through a precise control of band filling. Resistivity, magnetic susceptibility and specific heat measurements are carried out on a series of high-quality…
Based on the {\it ab-initio} band structure for Na$_x$CoO$_2$ we derive the single-electron energies and the effective tight-binding description for the $t_{2g}$ bands using projection procedure. Due to the presence of the…
The band structures of ordered and thermally disordered Li$_2$Mo$_{12}$O$_{34}$ are calculated by use of ab-initio DFT-LMTO method. The unusual, very 1-dimensional band dispersion obtained in previous band calculations is confirmed for the…
We systematically analyze the influence of the superconducting gap symmetry and the electronic structure on the dynamical spin susceptibility in superconducting Na_xCoO_2$\cdot y$H_2O within a three different models: the single a_{1g}-band…
We report specific heat, resistivity and susceptibility measurements at different temperatures, magnetic fields, and pressures to provide solid evidence of CoS2 being a marginal Fermi liquid. The presence of a tricritical point in the phase…
We calculated the structural, electronic and magnetic properties of FeSe within density-functional theory at the generalized gradient approximation level. First, we studied how the bandwidth of the d-bands at the Fermi energy are…
Correlation effects in CuO$_2$ layers give rise to a complicated landscape of collective excitations in high-T$_{\rm c}$ cuprates. Their description requires an accurate account for electronic fluctuations at a very broad energy range and…
The influence of long-range spin and charge fluctuations on spectra of the two-dimensional fermionic Hubbard model is considered using the strong coupling diagram technique. Infinite sequences of diagrams containing ladder inserts, which…
We have calculated the one-electron susceptibility of hydrated NaxCoO2 and find strong nesting nearly commensurate with a 2X2 superstructure. The nesting involves about 70% of all electrons at the Fermi level and is robust with respect to…
The nature of electronic states due to strong correlation and geometric frustration on the triangular lattice is investigated in connection to the unconventional insulating state of Na$_x$CoO$_2$ at $x=0.5$. We study an extended Hubbard…