2003/02/28 by Yoshihiko Nonomura, Xiao Hu, Nonomura, Yoshihiko +1
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Quantum many-body systems #Theoretical and Computational Physics #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.cond-mat/0302597
4 pages, 9 eps figures, using RevTeX4
arxiv created 2003/02/28 · arxiv updated 2009/11/30
Vortex states in high-T\rm c superconductors with point defects are studied by large-scale Monte Carlo simulations of the three-dimensional frustrated XY model. A critical point is observed on the first-order phase boundary between the vortex slush and vortex liquid phases. A step-like anomaly of the specific heat is detected in simulations of finite systems, similar to an experimental observation [F.~Bouquet \it et al., Nature (London) \bf 411, 448 (2001)]. However, it diminishes with increasing system size, and the number and size distribution of thermally-excited vortex loops show continuous behaviors around this anomaly. Therefore, the present study suggests a crossover rather than a thermodynamic phase transition above the critical point.