arXiv subjects

A. Sudbo

Publications and source records attributed to A. Sudbo.

38 records · Page 3Linked to original sources

arXiv1996

Vortex-Loop Unbinding and Flux-Line Lattice Melting in Superconductors

We study the interplay between a novel vortex-loop unbinding in finite magnetic field at T=T_V and flux-line lattice (FLL) melting at T=T_M in type-II superconductors. The FLL melts due to nucleation of vortex loops parallel to c-axis, connected to flux lines. For moderate anisotropy, phase coherence along c-axis is lost at T_V > T_M due to an ab-plane vortex-loop unbinding with loops located close to thermal FLL fluctuations. For large anisotropy, phase coherence along c-axis is lost at T_V < T_M due to nucleation of ab-plane vortex-loops uncorrelated to flux lines.

cond-mat↗

arXiv1996

Phase separation and the existence of superconductivity in a one-dimensional copper-oxygen model

The phase separation instability occurring with increasing nearest-neighbor repulsion V in a two-band Hubbard model (CuO chain) is discussed. Quantum Monte Carlo simulations indicate that this transition is associated with a level-crossing if the filling fraction is close to 1 (half-filled lower band). Spin-density-wave fluctuations then dominate before phase separation. Superconducting fluctuations dominate only at considerably higher doping levels.

cond-mat↗