On Gossamer Metals and Insulating Behavior

TL;DR

This paper extends the Gossamer technique to metallic states, showing how strong correlations can make metals resemble insulators, inspired by phase diagrams of V2O3 and f-electron systems.

Contribution

It introduces a Gossamer metal model that describes a continuous transition from metallic to insulating behavior driven by Coulomb correlations.

Findings

Gossamer metal becomes indistinguishable from insulator at high correlations

The model explains continuous metal-insulator transitions in correlated materials

Phase diagrams of V2O3 and f-electron systems are consistent with the model

Abstract

We extend the Gossamer technique recently proposed to describe superconducting ground states to metallic ground states. The gossamer metal in a single band model will describe a metallic phase that becomes arbitrarily hard to differentiate from an insulator as one turns the Coulomb correlations up. We were motivated by the phase diagram of V$_2$O$_3$ and f-electron systems which have phase diagrams in which a line of first order metal-insulator transition ends at a critical point above which the two phases are indistinguishable. This means that one can go continuously from the metal to the ``insulator'', suggesting that they might be the same phase.