Hole Dynamics in Two-Dimensional Antiferromagnetic Mott Insulators

TL;DR

This study investigates the dispersion relation of doped holes in 2D antiferromagnetic Mott insulators, revealing a transition from a k^4 to a k^2 law with pair-hopping, and suggests a link to superconductivity.

Contribution

It demonstrates how pair-hopping processes alter hole dispersion and potentially induce superconductivity in 2D Mott insulators.

Findings

Dispersion follows a k^4 law near (0,pi) and (pi,0) points.

Pair-hopping changes dispersion to a k^2 law.

Added pair-hopping promotes coherence and superconductivity.

Abstract

The dispersion relation of a doped hole in the half-filled 2D Hubbard model is shown to follow a k^4 law around the (0,pi) and (pi,0) points in the Brillouin zone. Upon addition of pair-hopping processes this dispersion relation is unstable towards a k^2 law. The above follows from T=0 Quantum Monte calculations of the single particle spectral function A(k, omega) on 16 X 16 lattices. We discuss finite dopings and argue that the added term restores coherence to charge dynamics and drives the system towards a d_x^2 - y^2 superconductor.