Scaling behavior in the optical conductivity of the two dimensional systems of strongly correlated electrons based on the U(1) slave-boson approach to the t-J Hamiltonian

TL;DR

This paper investigates the quantum scaling behavior of optical conductivity in two-dimensional strongly correlated electron systems using the U(1) slave-boson approach, highlighting the role of gauge field fluctuations in the low-frequency regime.

Contribution

It demonstrates that gauge field fluctuations, rather than spin pair excitations, drive the w/T scaling behavior in the optical conductivity of these systems.

Findings

Gauge field fluctuations cause the low-frequency w/T scaling behavior.

Scaling behavior appears near the critical hole concentration for superconductivity.

Nodal spinons contribute to the Drude peak in optical conductivity.

Abstract

The U(1) holon-pair boson theory of Lee and Salk(Phys. Rev. B 64, 052501 (2001)) is applied to investigate the quantum scaling behavior of optical conductivity in the two dimensional systems of strongly correlated electrons. We examine the role of both the gauge field fluctuations and spin pair excitations on the w/T scaling behavior of the optical conductivity. It is shown that the gauge field fluctuations but not the spin pair excitations are responsible for the scaling behavior in the low frequency region w/T <<1. Importance for the contribution of the nodal spinons to the Drude peak is discussed. It is shown that the w/T scaling behavior is manifest in the low frequency region at low hole concentrations close to a critical concentration at which superconductivity arises at T=0K.