Fully frustrated XY model with nextnearestneighbor interaction
Abstract
We investigate a fully frustrated XY model with nearestneighbor (NN) and nextnearestneighbor (NNN) couplings which can be realized in Josephson junction arrays. We study the phase diagram for 0<=x<=1 (x is the ratio between NNN and NN couplings). When x<1/2 an Ising transition and a BerezinskiiKosterlitzThouless transition are present. Both critical temperatures decrease with increasing x. For x>1/2 the array undergoes a sequence of two transitions. On raising the temperature first the two sublattices decouple from each other and then, at higher temperatures, each sublattice becomes disordered. The structure of phase diagram remains the same if weak interaction with further neighbors is included.
 Publication:

Physical Review B
 Pub Date:
 October 2000
 DOI:
 10.1103/PhysRevB.62.R9287
 arXiv:
 arXiv:condmat/0004495
 Bibcode:
 2000PhRvB..62.9287F
 Keywords:

 74.50.+r;
 64.60.Fr;
 75.40.Mg;
 Tunneling phenomena;
 point contacts weak links Josephson effects;
 Equilibrium properties near critical points critical exponents;
 Numerical simulation studies;
 Condensed Matter  Statistical Mechanics;
 Condensed Matter  Superconductivity
 EPrint:
 11 pages, 5 figures