Here, we demonstrate the electrochemical fluorination of La2CuO4 in an all-solid-state cell. This method fluorine intercalation is controllable and reproducible, offering a precise adjustment hole doping thus tuning superdiamagnetic (i.e., perfect diamagnetic behavior superconductor) properties. The fluorinated La2CuO4Fx samples showed increase Tc response with increasing content x up to ∼0.2. ...

Many important questions for high-Tc cuprates are closely related to the insulating nature of parent compounds. While there has been intensive discussion on this issue, all arguments rely strongly on, or are closely related to, the correlation strength of the materials. Clear understanding has been seriously hampered by the absence of a direct measure of this interaction, traditionally denoted ...

In this paper we present the atomic-layer-by-layer oxide molecular beam epitaxy (ALL-oxide MBE) which has been recently installed in the Max-Planck Institute for Solid State Research and we report on its present status, providing some examples that demonstrate its successful application in the synthesis of different layered oxides, with particular reference to superconducting La2CuO4 and insula...

The magnetic excitations of the square-lattice spin-1/2 antiferromagnet and high- T(c) parent compound La2CuO4 are determined using high-resolution inelastic neutron scattering. Sharp spin waves with absolute intensities in agreement with theory including quantum corrections are found throughout the Brillouin zone. The observed dispersion relation shows evidence for substantial interactions bey...

We present angle-resolved photoemission spectroscopy (ARPES) data on undoped La2CuO4, indicating polaronic coupling between bosons and charge carriers. Using a shell model, we calculate the electron-phonon coupling and find that it is strong enough to give self-trapped polarons. We develop an efficient method for calculating ARPES spectra in undoped systems. Using the calculated couplings, we f...

We present measurements of the in-plane (κ ab) and out-of-plane (κc) thermal conductivity of Pr2CuO4 and Gd2CuO4 single crystals. The anisotropy gives strong evidence for a large contribution of magnetic excitations to κ ab , i.e. for a heat current within the CuO2 planes. However, the absolute values of κmag are lower than previous results on La2CuO4. These differences probably arise from devi...

We have studied the charge dynamics of Sr-doped La2CuO4 at hole concentration p = 0.07. We observed a clear indication of the competition between two Wigner lattice orders: One corresponds to a Tc = 15 K superconductivity and the other to Tc = 30K. Our results naturally explain the recent observation of metallic transport in extremely low (1%) Sr-doped La2CuO4 and establish a novel insulator to...

Band calculations for supercells of La((2-x))Ba(x)CuO(4) show that the rigid band model for doping is less adequate than what is commonly assumed. In particular, weak ferromagnetism can appear locally around clusters of high Ba concentration. The clustering is important at large dilution, and averaged models for magnetism, such as the virtual crystal approximation, are unable to stabilize magne...

Here we correct, extend, and clarify results concerning the spin Hamiltonian HS used to describe the ground manifold of Hubbard models for magnetic insulators in the presence of spin-orbit interactions. Most of our explicit results are for a tetragonal lattice as applied to some of the copper oxide lamellar systems and are obtained within the approximation that HS consists of a sum of nearest-n...