Hole-Density Evolution of the One-Particle Spectral Function in Doped Ladders

TL;DR

This paper investigates how the one-particle spectral function in doped $t-J$ ladders evolves with doping, revealing a transition from narrow to quasi-noninteracting bands and similarities with 2D cuprate photoemission features.

Contribution

It introduces a high-precision computational technique to analyze spectral functions in doped ladders, showing detailed evolution with doping and connections to experimental observations.

Findings

Spectral function evolves from narrow to quasi-noninteracting bands with doping.

Presence of a gap at $( ext{π,0})$ near half-filling due to hole pairing.

Finite line-widths develop in low-energy peaks away from the chemical potential.

Abstract

The spectral function $A({\bf q}, \omega)$ of doped $t-J$ ladders is presented on clusters with up to $2 \times 20$ sites at zero temperature applying a recently developed technique that uses up to $\sim 6 \times 10^6$ rung-basis states. Similarities with photoemission results for the 2D cuprates are observed, such as the existence of a gap at $(\pi,0)$ near half-filling (caused by hole pair formation) and flat bands in its vicinity. These features should be observable in ARPES experiments on ladders. The main result of the paper is the nontrivial evolution of the spectral function from a narrow band at $x=0$, to a quasi-noninteracting band at $x \geq 0.5$. It was also observed that the low-energy peaks of a cluster spectra acquire finite line-widths as their energies move away from the chemical potential.