J. M. Wheatley

NONMAGNETIC IMPURITIES IN TWO-DIMENSIONAL SUPERCONDUCTORS

A numerical approach to disordered two-dimensional superconductors described by BCS mean-field theory is outlined. The energy gap and the superfluid density at zero temperature and the quasiparticle density of states are studied. The method involves approximate self-consistent solutions of the Bogolubov--de Gennes equations on finite square lattices. Where comparison is possible, the results of standard analytic approaches to this problem are reproduced. Detailed modeling of impurity effects is practical using this approach. The range of the impurity potential is shown to be of quantitative importance in the case of strong potential scatterers. We discuss the implications for experiments, such as the rapid suppression of superconductivity by Zn doping in copper-oxide superconductors.

FLUX-LATTICE MELTING AND DEPINNING IN THE WEAKLY FRUSTRATED TWO-DIMENSIONAL XY MODEL

Monte Carlo simulations of the frustrated 2D XY model were carried out at small commensurate values of the frustration

Superconducting upper critical field near a 2D van Hove singularity

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Stability of d-wave pairing in two dimensions

. For

Umklapp scattering from spin fluctuations in copper oxides

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Upper critical field in a spin-charge-separated superconductor.

a single transition was observed at which phase coherence (finite helicity modulus) and vortex lattice orientational order vanish together. For

THEORY OF OPTICAL ABSORPTION IN HIGH-TEMPERATURE SUPERCONDUCTORS

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Combination rules, charge symmetry, and Hall effect in cuprates.

a new phase in which phase coherence is absent but orientational order persists was observed. Where comparison is possible, the results are in detailed agreement with the behavior of the lattice Coulomb gas model of vortices. It is argued that the helicity modulus of the frustrated 2D XY model vanishes for any finite temperature in the limit of weak frustration

Spin-Charge coupling in doped Mott Insulators

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Superconductivity theory ready for testing

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