Mott transition between a spin-liquid insulator and a metal in three dimensions

TL;DR

This paper investigates a continuous Mott transition between a spin-liquid insulator and a metal in three dimensions, predicting specific heat behavior and transport features, with potential experimental relevance to Na4Ir3O8.

Contribution

It introduces a theoretical framework for a continuous 3D Mott transition incorporating gauge fluctuations and predicts observable signatures in specific heat and conductivity.

Findings

Specific heat at transition: C=T ln ln(1/T)

Electrical conductivity shows a minimum near transition

Spectral function of Na4Ir3O8 analyzed at criticality

Abstract

We study a bandwidth controlled Mott metal-insulator transition (MIT) between a Fermi liquid metal and a quantum spin-liquid insulator at half-filling in three dimensions (3D). Using a slave rotor approach, and incorporating gauge field fluctuations, we find a continuous MIT and discuss the finite temperature crossovers around this critical point. We show that the specific heat C=T ln ln (1/T) at the MIT and argue that the electrical transport on the metallic side near the transition should exhibit a `conductivity minimum' as a function of temperature. A possible candidate to test these predictions is the 3D spin liquid insulator Na4Ir3O8 which exhibits a pressure-tuned transition into a metallic phase. We also present the electron spectral function of Na4Ir3O8 at the transition.