R. J. Gooding

Theory of electron-hole asymmetry in doped CuO2 planes.

Consistent with experiment, for the hole-doped materials short-ranged incommensurate spin orderings are induced, whereas for the electron-doped system only commensurate spin correlations are found. Further, we propose that there is an important difference between the spatial distributions of mobile carriers for these two systems: for the hole-doped material the quasiparticles tend to stay far apart from one another, whereas for the electron-doped material we find tendencies consistent with the clustering of carriers, and possibly of low-energy fluctuations into an electronic phase-separated state. Phase separation in this material is consistent with the midgap states found by recent angle-resolved photoemission spectroscopy studies. Last, we propose the extrapolation of an approach based on the [ital t]-[ital t][prime]-[ital J] model to the hole-doped 123 system.

Theory of coexisting transverse-spin freezing and long-ranged antiferromagnetic order in lightly doped La2-xSrxCuO4.

We provide an explanation of the spin-freezing transition recently observed by Chou et al. [Phys. Rev. Lett. 71, 2323 (1993)] in

Comprehensive numerical and analytical study of two holes doped into the two-dimensional t−J model

{\mathrm{La}}_{2\mathrm{\ensuremath{-}}\mathit{x}}

A comprehensive dynamical study of nucleation and growth in a one- dimensional shear martensitic transition

{\mathrm{Sr}}_{\mathit{x}}

Variational Monte Carlo Study of Anderson Localization in the Hubbard Model

{\mathrm{CuO}}_{4}

Electronic properties of disordered corner-sharing tetrahedral lattices

for x\ensuremath{\lesssim}0.02. We propose that topological excitations of the two-dimensional Heisenberg quantum antiferromagnet having noncoplanar transverse components have a pair-interaction energy that qualitatively and quantitatively agrees with the observed values of spin-freezing temperature as a function of doping.

Examining the metal-to-insulator transitions inLi1+xTi2−xO4andLiAlyTi2−yO4with a quantum site percolation model

We report on a detailed examination of numerical results and analytical calculations devoted to a study of two holes doped into a two-dimensional, square lattice described by the t-J model. Our exact diagonalization numerical results represent the first solution of the exact ground state of 2 holes in a 32-site lattice. Using this wave function, we have calculated several important correlation functions, notably the electron momentum distribution function and the hole-hole spatial correlation function. Further, by studying similar quantities on smaller lattices, we have managed to perform a finite-size scaling analysis. We have augmented this work by endeavouring to compare these results to the predictions of analytical work for two holes moving in an infinite lattice. This analysis relies on the canonical transformation approach formulated recently for the t-J model. From this comparison we find excellent correspondence between our numerical data and our analytical calculations. We believe that this agreement is an important step helping to justify the quasiparticle Hamiltonian, and in particular, the quasiparticle interactions, that result from the canonical transformation approach. Also, the analytical work allows us to critique the finite-size scaling ansatzes used in our analysis of the numerical data. One important feature that we can infer from this successful comparison involves the role of higher harmonics in the two-particle, d-wave symmetry bound state -- the conventional (\cos(k_x) - \cos(k_y)) term is only one of many important contributions to the d-wave symmetry pair wave function.

Spin twists, domain walls, and the cluster spin-glass phase of weakly doped cuprates

An extensive experimental and theoretical effort has led to a largely complete mapping of the magnetic phase diagram of