Doping the Mott insulating state of the triangular-lattice Hubbard model reveals the Sordi transition

TL;DR

This paper demonstrates the existence of a first-order metal-metal transition, known as the Sordi transition, in doped Mott insulators on a triangular lattice, using larger clusters and a different computational method, highlighting its experimental relevance.

Contribution

It provides evidence for the Sordi transition in larger clusters and with a different method, confirming its physical reality beyond finite size effects.

Findings

Observation of the Sordi transition on larger clusters.

Confirmation of the transition's relevance for experiments.

Use of dynamical cluster approximation instead of cellular DMFT.

Abstract

It has been reported that upon doping a Mott insulator, there can be a crossover to a pseudogaped metallic phase followed by a first-order transition to another thermodynamically stable metallic phase. We call this first-order metal-metal transition the Sordi transition. It was argued that the initial reports of Sordi transitions at finite temperature could be explained by finite size effects and biases related to the model and method used. In this work, we report the Sordi transition on larger clusters at finite temperature on a triangular lattice, where long-range antiferromagnetic fluctuations are frustrated, using a different method, the dynamical cluster approximation instead of the cellular dynamical mean-field theory. This demonstrates that this first-order transition is a directly observable transition in doped Mott insulators and that it is relevant for experiments on candidate spin-liquid organic materials.