https://doi.org/10.1140/epjb/e2016-60478-y
Regular Article
Superconductor-insulator transition of Josephson-junction arrays on a honeycomb lattice in a magnetic field
Laboratório Associado de Sensores e Materiais,
Instituto Nacional de Pesquisas Espaciais, 12227-010
São José dos Campos, SP, Brazil
a e-mail: enzo@las.inpe.br
Received:
15
June
2015
Received in final form:
24
October
2015
Published online:
14
March
2016
We study the superconductor to insulator transition at zero temperature in a Josephson-junction array model on a honeycomb lattice with f flux quantum per plaquette. The path integral representation of the model corresponds to a (2 + 1)-dimensional classical model, which is used to investigate the critical behavior by extensive Monte Carlo simulations on large system sizes. In contrast to the model on a square lattice, the transition is found to be first order for f = 1 / 3 and continuous for f = 1 / 2 but in a different universality class. The correlation-length critical exponent is estimated from finite-size scaling of vortex correlations. The estimated universal conductivity at the transition is approximately four times its value for f = 0. The results are compared with experimental observations on ultrathin superconducting films with a triangular lattice of nanoholes in a transverse magnetic field.
Key words: Solid State and Materials
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2016