Mott Fermionic "Quantum" Criticality Beyond Ginzburg-Landau-Wilson

TL;DR

This paper proposes a new fermionic fluctuation-based framework for understanding the Mott critical point, challenging traditional bosonic mode theories and explaining experimental anomalies with a novel universality class.

Contribution

It introduces a fermionic fluctuation perspective for the Mott transition, revealing a new universality class with quantum effects at finite temperature.

Findings

Agreement with unexplained experimental critical exponents

Identification of a new universality class for the Mott transition

Quantum effects play a central role in the finite temperature criticality

Abstract

The Mott critical point between a metal and a correlated insulator has usually been studied via density or spin density bosonic mode fluctuations according to the standard Ginzburg-Landau-Wilson phase transition paradigm. A moment's reflection leads to increasing doubts that such an approach should work as the transition is nonmagnetic, voiding the relevance of spin density modes. Charge density modes are irrelevelant since the long range Coulomb interaction leads to a large plasmon gap and their incompressibility. In solidarity with these doubts, recent measurements of the Mott critical point in low dimensional organic materials yield critical exponents in violent diasagreement with the bosonic mode criticality lore. We propose that fermionic fluctuations control the behavior of the Mott transition. The transition thus has an intrinsic quantum aspect despite being a finite temperature phase transition. We develop this hitherto unexplored physics, obtain experimental predictions and find agreement with one of the novel unexplained experimental exponents. We conclude that this Mott transition corresponds to a new universality class of finite temperature critical points that contains quantum effects and cannot be accounted for by conventional Ginzburg-Landau-Wilson wisdom.