Type-II Bose-Mott insulators

TL;DR

This paper predicts a new phase called the 'type-II Mott insulator' near the superconductor transition, featuring a regular array of supercurrent 'wires' analogous to magnetic flux lattices, with implications for high-Tc superconductors.

Contribution

It introduces the concept of a 'type-II Mott insulator' with a flux-like supercurrent lattice, based on a duality framework, extending understanding of bosonic Mott insulators.

Findings

Prediction of a 'current lattice' phase near the superconductor transition.

Establishment of a duality between supercurrent arrays and magnetic flux lattices.

Potential experimental approach to detect preformed Cooper pairs in high-Tc superconductors.

Abstract

The Mott insulating state formed from bosons is ubiquitous in solid He-4, cold atom systems, Josephson junction networks and perhaps underdoped high-Tc superconductors. We predict that close to the quantum phase transition to the superconducting state the Mott insulator is not at all as featureless as is commonly believed. In three dimensions there is a phase transition to a low temperature state where, under influence of an external current, a superconducting state consisting of a regular array of 'wires' that each carry a quantized flux of supercurrent is realized. This prediction of the "type-II Mott insulator" follows from a field theoretical weak-strong duality, showing that this 'current lattice' is the dual of the famous Abrikosov lattice of magnetic fluxes in normal superconductors. We argue that this can be exploited to investigate experimentally whether preformed Cooper pairs exist in high-Tc superconductors.