Dynamic Exponent of t-J and t-J-W Model

TL;DR

This paper investigates the dynamic exponent of the two-dimensional t-J model with a two-particle term, revealing a transition from anomalous to conventional behavior as the two-particle term is introduced.

Contribution

It provides the first calculation of the Drude weight scaling in the t-J model with a two-particle term, demonstrating a change in the dynamic exponent from 4 to 2.

Findings

Drude weight scales as δ^2 for W=0

Dynamic exponent z=4 at W=0

Dynamic exponent z=2 when W is non-zero

Abstract

Drude weight of optical conductivity is calculated at zero temperature by exact diagonalization for the two-dimensional t-J model with the two-particle term, $W$. For the ordinary t-J model with $W$=0, the scaling of the Drude weight $D \propto \delta^2$ for small doping concentration $\delta$ is obtained, which indicates anomalous dynamic exponent $z$=4 of the Mott transition. When $W$ is switched on, the dynamic exponent recovers its conventional value $z$=2. This corresponds to an incoherent-to-coherent transition associated with the switching of the two-particle transfer.