Strong evidence for the three-dimensional Fermi liquid behaviour of quasiparticles in high-TCT_{\rm C} cupurates

It is generally believed that behaviours of quasiparticles (holes) in high-$T_{\rm C}$ cupurates should be attributed to the two-dimensional (2D) electronic states in the CuO$_{2}$ planes. The various anomalies of the transport coefficients for temperatures above $T_{\rm C}$ are long-standing insoluble puzzles and cause serious controversy. Here we reanalyse the published experimental date of LSCO cupurates. We find that the normal-state susceptibility, resistivity, Hall coefficient etc vary precisely as $T^{2}\ln T$ as a function of temperature $T$ in agreement with the prediction of the Fermi liquid model. The quasiparticles are shown to definitely behave as a 3D Fermi liquid. Various attempts to describe the system in terms of non-Fermi liquids,e.g. the RVB state, seem to be erroneous.Comment: 2 pages, 3 Postscript figures, To appear in Physica

Charge Order in a Two-Dimensional Kondo Lattice Model

The possibility of charge order is theoretically examined for the Kondo lattice model in two dimensions, which does not include bare repulsive interactions. Using two complementary numerical methods, we find that charge order appears at quarter filling in an intermediate Kondo coupling region. The charge ordered ground state is an insulator exhibiting an antiferromagnetic order at charge-poor sites, while the paramagnetic charge-ordered state at finite temperatures is metallic with pseudogap behavior. We confirm that the stability of charge order is closely related with the local Kondo-singlet formation at charge-rich sites. Our results settle the controversy on charge order in the Kondo lattice model in realistic spatial dimensions.Comment: 5 pages, 4 figure

Charge Order with a Noncoplanar Triple-Q Magnetic Order on a Cubic Lattice

Ground state of the periodic Anderson model on a cubic lattice is investigated by mean-field calculations, with focusing on the possibility of charge ordering. We show that three different charge-ordered phases appear at 3/2 filling, which are accompanied by ferromagnetic, noncoplanar triple-Q, and ferrimagnetic order, respectively. The triple-Q magnetic order is likely stabilized by emergent geometrical frustration in the charge-ordered phase with the ordering wave vector (pi,pi,pi). We show that the nearest-neighbor hopping between localized electrons stabilizes the triple-Q phase relative to the other two phases. We also discuss the electronic structure in the triple-Q charge-ordered phase.Comment: 6 pages, 3 figure