First Order Superconductor to Insulator Transition: Evidence for a Supersolid Phase

TL;DR

This study investigates the superconductor-insulator transition with Coulomb interactions, revealing a first order transition at half filling and two second order transitions off half filling, without evidence of a supersolid phase.

Contribution

It provides new Monte Carlo evidence on the nature of phase transitions and the absence of a supersolid phase in this model.

Findings

First order transition at half filling with non-zero $S_{\pi,\pi}$

Two separate second order transitions off half filling

No evidence of a supersolid phase observed

Abstract

The superconductor to insulator transition in the presence of long-range Coulomb interactions is studied using Monte Carlo techniques. At integer filling the transition is second order. At half filling we find evidence of a first order transition to a state with non-zero $S_{\pi,\pi}$. No intervening supersolid phase is observed. Off half-filling two separate transitions are found. The transition from the superconducting to a supersolid phase is second order followed by another second order transition between the supersolid and an insulating phase.