arXiv subjects

A. J. Berlinsky

Publications and source records attributed to A. J. Berlinsky.

22 records · Page 2Linked to original sources

arXiv1996

Impurity scattering and localization in $d$-wave superconductors

Strong evidence is presented for the localization of low energy quasiparticle states in disordered $d$-wave superconductors. Within the framework of the Bogoliubov-de Gennes (BdG) theory applied to the extended Hubbard model with a finite concentration of non-magnetic impurities, we carry out a fully self-consistent numerical diagonalization of the BdG equations on finite clusters containing up to $50\times 50$ sites. Localized states are identified by probing their sensitivity to the boundary conditions and by analyzing the finite size dependence of inverse participation ratios.

cond-mat↗

arXiv1995

Vortex State in a d-Wave Superconductor

We discuss the physics of the vortex state in a $d$-wave superconductor, using the phenomenological Ginzburg-Landau theory, where many novel phenomena arise from the small admixture of the $s$-wave component induced by spatial variations in the dominant $d$-wave. Properties of an isolated vortex and of the Abrikosov vortex lattice are studied by means of analytic and numerical methods. An isolated vortex has a considerable structure, with four ``extra'' nodes in the $s$-wave order parameter symmerically placed around the core and an amplitude forming a four-lobe profile decaying as $1/r^2$ at large distances. The supercurrent and magnetic field distributions are also calculated. The Abrikosov lattice is in general oblique with the precise shape determined by the magnetic field and $s$-$d$ mixing parameter $ε_v$. The magnetic field distribution in the Abrikosov state has two nonequivalent saddle points resulting in the prediction of a double peak line shape in $μ$SR and NMR experiments as a test of a $d$-wave symmetry. Detailed comparison is made with existing experimental data and new experiments are proposed to test for the predicted effects.

cond-mat↗

arXiv1995

GINZBURG-LANDAU THEORY OF VORTICES IN $d$-WAVE SUPERCONDUCTORS

Ginzburg-Landau theory is used to study the properties of single vortices and of the Abrikosov vortex lattice in a $d_{x^2-y^2}$ superconductor. For a single vortex, the $s$-wave order parameter has the expected four-lobe structure in a ring around the core and falls off like $1/r^2$ at large distances. The topological structure of the $s$-wave order parameter consists of one counter-rotating unit vortex, centered at the core, surrounded by four symmetrically placed positive unit vortices. The Abrikosov lattice is shown to have a triangular structure close to $T_c$ and an oblique structure at lower temperatures. Comparison is made to recent neutron scattering data.

cond-mat↗

arXiv1993

The Kagome Antiferromagnet with Defects: Satisfaction, Frustration, and Spin Folding in a Random Spin System

It is shown that site disorder induces noncoplanar states, competing with the thermal selection of coplanar states, in the nearest neighbor, classical kagome Heisenberg antiferromagnet (AFM). For weak disorder, it is found that the ground state energy is the sum of energies of separately satisfied triangles of spins. This implies that disorder does not induce conventional spin glass behavior. A transformation is presented, mapping ground state spin configurations onto a folded triangular sheet (a new kind of ``spin origami'') which has conformations similar to those of tethered membranes.

cond-mat↗