Reentrant behavior of the phase stiffness in Josephson junction arrays.
The phase diagram of a 2D Josephson junction array with large substrate resistance, described by a quantum XY model, is studied by means of Fourier path-integral Monte Carlo. A genuine Berezinskii-Kosterlitz-Thouless transition is found up to a threshold value g( small star, filled ) of the quantum coupling, beyond which no phase coherence is established. Slightly below g( small star, filled ) the phase stiffness shows a reentrant behavior with temperature, in connection with a low-temperature disappearance of the superconducting phase, driven by strong nonlinear quantum fluctuations.
Capriotti
Luca
L
Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106, USA.
Cuccoli
Alessandro
A
Fubini
Andrea
A
Tognetti
Valerio
V
Vaia
Ruggero
R