author = "Granato, Enzo",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Superconductor-insulator transition in Josephson-junction arrays 
                         on a honeycomb lattice and ultra-thin superconducting films with a 
                         periodic lattice of nanoholes",
            booktitle = "Resumos...",
                 year = "2015",
         organization = "Encontro Nacional de F{\'{\i}}sica da Mat{\'e}ria Condensada, 
             abstract = "The zero-temperature superconductor to insulator transition is 
                         studied in a self-charging model of Josephson-junction arrays in 
                         an external magnetic Ĝeld corresponding to f flux quantum per 
                         plaquette. The model can be physically realized as two-dimensional 
                         arrays of weakly coupled superconducting grains and ultra-thin 
                         superconducting films with a triangular pattern of nanoholes 
                         [1,2]. When charging effects due to the small capacitance of the 
                         grains or junctions dominate, strong quantum fluctuations of the 
                         phase of the superconducting order parameter drive the system into 
                         an insulating phase at zero temperature leading to a 
                         superconductor to insulator transition as a function of charging 
                         energy. In presence of an external magnetic field, frustration 
                         effects lead to distinct universality classes which depend on the 
                         geometry of the array. For a Josephson-junction array on square 
                         lattice, the universality class of these transitions have already 
                         been investigated in detail numerically [3]. However, for a 
                         Josephson-junction array on a honeycomb lattice there are very few 
                         results. Path integral Monte Carlo simulations of the equivalent 
                         (2+1)-dimensional classical model are used to study the phase 
                         transition and critical behavior. For f = 0 and f = 1 = 2, the 
                         transition is second order and the corresponding correlation 
                         length critical exponents are estimated from finite-size 
  conference-location = "Foz do Igua{\c{c}}u, PR",
      conference-year = "24-28 maio",
             language = "en",
        urlaccessdate = "04 dez. 2020"