2000/07/11 by Kyungwha Park, David A. Huse · 29 citations
Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Algorithm #Humanities #Mathematics #Philosophy #Physics #Physics of Superconductivity and Magnetism #Quantum, superfluid, helium dynamics #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.64.134522
published in Physical review. B, Condensed matter 64(13) (American Physical Society) · 30 pages including figures
arxiv created 2000/07/11 · openalex publication_date 2001/09/12 · arxiv updated 2012/08/16 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
In classical XY kagom'e antiferromagnets, there can be a low-temperature phase where \ensuremathψ3=e^i3\ensuremathθ has quasi-long-range order but \ensuremathψ is disordered, as well as more conventional antiferromagnetic phases where \ensuremathψ is ordered in various possible patterns (\ensuremathθ is the angle of orientation of the spin). To investigate when these phases exist in a physical system, we study superconducting kagom'e wire networks in a transverse magnetic field when the magnetic flux through an elementary triangle is a half of a flux quantum. Within Ginzburg-Landau theory, we calculate the helicity moduli of each phase to estimate the Kosterlitz-Thouless (KT) transition temperatures. Then at the KT temperatures, we estimate the barriers to move vortices and the effects that lift the large degeneracy in the possible \ensuremathψ patterns. The effects we have considered are inductive couplings, nonzero wire width, and the order-by-disorder effect due to thermal fluctuations. The first two effects prefer q=0 patterns, while the last one selects a √(3)\ifmmode×\else\texttimes\fi√(3) pattern of supercurrents. Using the parameters of recent experiments, we conclude that at the KT temperature, the nonzero wire width effect dominates, which stabilizes a conventional superconducting phase with a q=0 current pattern. However, by adjusting the experimental parameters, for example by bending the wires a little, it appears that the \ensuremathψ3 superconducting phase can instead be stabilized. The barriers to vortex motion are low enough that the system can equilibrate into this phase.