Sequence of phase transitions induced in an array of Josephson junctions by their crossover to pi-state

TL;DR

This paper investigates how temperature-induced transitions between 0 and pi states in Josephson junction arrays lead to multiple phase transitions, with detailed phase diagrams for various lattice geometries.

Contribution

It reveals that Josephson junction arrays can undergo multiple phase transitions due to crossover to the pi-state, expanding understanding of their complex phase behavior.

Findings

Multiple phase transitions observed in Josephson junction arrays.

Phase diagrams constructed for square, honeycomb, and triangular lattices.

Sequence of 2 to 4 phase transitions depending on lattice type.

Abstract

We show that the transition of Josephson junctions between the conventional and pi states caused by the decrease in temperature induces in a regular two-dimensional array of such junctions not just a single phase transition between two phases with different ordering but a sequence of two, three or four phase transitions. The corresponding phase diagrams are constructed for the cases of bipartite (square or honeycomb) and triangular lattices.