Low-energy Spectra of the t-J-Type Models Studied by Variational Approach

TL;DR

This paper investigates the low-energy spectra of t-J-type models relevant to high-temperature cuprate superconductors using variational wave functions, revealing insights into their ground states and excitations consistent with experimental observations.

Contribution

It introduces a variational approach to study the d-wave RVB states in t-J models, providing new understanding of their spectral properties and excitations.

Findings

Fermi surface geometry matches photoemission data

Spectral weights explain tunneling conductance features

Strong correlation effects produce unique spectral properties

Abstract

We discuss recent progress of understanding the phenomena observed in high Tc cuprates by studying the d-wave resonating-valence-bond (d-RVB) based trial wave functions for the 2-dimensional t-J-type models. Treat exactly the strong correlation between electrons by numerical approach, we examine the evolution of ground states described by different variational wave functions and properties of the quasi-hole and -particle excitations of the d-RVB superconducting (SC) state. Properties related to the Fermi surface geometry deduced from quasi-hole energy dispersion of the SC state is shown to be consistent with the observation by photoemission spectroscopy. With the calculated spectral weights (SW's) for adding and removing an electron, we found not only the anti-correlation between conductance peak height and width between peaks seen in tunneling experiments, but also unique properties due to strong correlation which need to be verified by future experiments.