相关论文: Stripe correlations in Na$_{0.75}$CoO$_2$
The sodium reordering in NaxCoO2 in the vicinity of room temperature is rationalized at high x in terms of phase transitions between square and striped phases. A striking hexagon-of-hexagons diffraction pattern observed for x=0.78 can be…
Ab initio band theory including correlations due to intra-atomic repulsion is applied to study charge disproportionation and charge- and spin-ordering in insulating Na$_{0.5}$CoO$_2$. Various ordering patterns (zigzag and two striped) for…
The layered sodium cobalt oxide NaxCoO2 is studied by electron diffraction for a wide range of sodium contents, 0.15<x<0.75. An extensive series of ordered Na ion-Na vacancy superlattices is found beyond the simple hexagonal average…
Band structure of metallic sodium cobaltate Na$_x$CoO$_2$ ($x$=0.33, 0.48, 0.61 0.72) has been investigated by local density approximation+Hubbard $U$ (LDA+$U$) method and within Gutzwiller approximation for the Co-$t_{2g}$ manifold.…
We have utilized neutron powder diffraction to probe the crystal structure of layered Na$_{x}$CoO$_{2}$ near the half doping composition of $x=$0.46 over the temperature range of 2 to 600K. Our measurements show evidence of a dynamic…
Transport measurements provide important characterizations of the nature of stripe order in the cuprates. Initial studies of systems such as La(1.6-x)Nd(0.4)Sr(x)CuO(4) demonstrated the strong anisotropy between in-plane and c-axis…
We present new x-ray and neutron scattering measurements of stripe order in La(1.875)Ba(0.125)CuO(4), along with low-field susceptibility, thermal conductivity, and specific heat data. We compare these with previously reported results for…
The relation between d-wave superconductivity and stripes is fundamental to the understanding of ordered phases in cuprates. While experimentally both phases are found in close proximity, numerical studies on the related Fermi-Hubbard model…
The correlations between stripe order, superconductivity, and crystal structure in La(2-x)Ba(x)CuO(4) single crystals have been studied by means of x-ray and neutron diffraction as well as static magnetization measurements. The derived…
Charge-order stripes of different types occur when copper oxides are doped with either heterovalent metal, like $La_{2-x}Sr_xCuO_4$, or oxygen, like $YBa_2Cu_3O_{6+y}$. The difference shows up in the doping dependence of their…
The electronic structure of Na$_x$CoO$_2$ revealed by recent photoemission experiments shows important deviations from band theory predictions. The six small Fermi surface pockets predicted by LDA calculations have not been observed as the…
Although all superconducting cuprates display charge-ordering tendencies, their low-temperature properties are distinct, impeding efforts to understand the phenomena within a single conceptual framework. While some systems exhibit stripes…
Recent experiments indicate that static stripe-like charge order is generic to the hole-doped copper oxide superconductors and competes with superconductivity. Here we show that a similar type of charge order is present in…
The ordering of Na ions in Na$_x$CoO$_2$ is investigated systematically by combining detailed density functional theory (DFT) studies with model calculations. Various ground state ordering patterns are identified, and they are in excellent…
Stripe phases are predicted and observed to occur in a class of strongly-correlated materials describable as doped antiferromagnets, of which the copper-oxide superconductors are the most prominent representative. The existence of stripe…
The temperature evolution of structural effects associated with charge (CO) and spin order (SO) in La$_{1.67}$Sr$_{0.33}$NiO$_{4}$ has been investigated using neutron powder diffraction. We report an anomalous shrinking of the $c/a$ lattice…
Revealing the predominant driving force behind symmetry breaking in correlated materials is sometimes a formidable task due to the intertwined nature of different degrees of freedom. This is the case for La2-xSrxNiO4+{\delta} in which…
One of the major themes in correlated electron physics over the last quarter century has been the problem of high-temperature superconductivity in hole-doped copper-oxide compounds. Fundamental to this problem is the competition between…
Holes doped into the CuO2 planes of cuprate parent compounds frustrate the antiferromagnetic order. The development of spin and charge stripes provides a compromise between the competing magnetic and kinetic energies. Static stripe order…
The effects of the stripe order on the optical spectra of La-based cuprates are reviewed. The main effect on the high Tc superconducting cuprates is to rapidly reduce the Josephson plasma frequency in the c-axis spectrum as a consequence of…