Universality Class of the Mott Transition

TL;DR

This study investigates the critical behavior of the Mott transition in a layered organic conductor, revealing that its critical exponents align with the Ising universality class regardless of system dimensionality.

Contribution

It demonstrates that the Mott-Hubbard transition's critical exponents belong to the Ising universality class, providing new insight into the universality of the Mott transition.

Findings

Critical exponents match Ising universality class

Thermoelectric effect clearly identifies transition point

Transition behavior is independent of system dimensionality

Abstract

Pressure dependence of the conductivity and thermoelectric power is measured through the Mott transition in the layer organic conductor EtMe3P[Pd(dmit)2]2. The critical behavior of the thermoelectric effect provides a clear and objective determination of the Mott-Hubbard transition during the isothermal pressure sweep. Above the critical end point, the metal-insulator crossing, determined by the thermoelectric effect minimum value, is not found to coincide with the maximum of the derivative of the conductivity as a function of pressure. We show that the critical exponents of the Mott-Hubbard transition fall within the Ising universality class regardless of the dimensionality of the system.