Angle-Resolved Photoelectron Spectroscopy Studies of the Many-Body Effects in the Electronic Structure of High-Tc Cuprates

TL;DR

This paper uses angle-resolved photoelectron spectroscopy (ARPES) to investigate many-body effects in high-temperature cuprate superconductors, modeling their electronic structure and exploring matrix element effects and correlations.

Contribution

It presents a Green's function model for cuprates' electronic structure and analyzes ARPES matrix element effects, including the 'waterfalls' dispersion anomaly and its relation to other experimental methods.

Findings

Model of Green's function for BSCCO's electronic properties

Detailed analysis of ARPES 'waterfalls' dispersion

Calculation of two-particle correlation functions in superconducting state

Abstract

After an extended introduction, the thesis considers the electronic properties of BSCCO and the recent progress in understanding the electronic structure of this material. The main result of this part of the work is a model of the Green's function that is later used for calculating the two-particle excitation spectrum. Then, the matrix element effects in the photoemission spectra of cuprates are discussed with a focus on the recently discovered anomalous behavior of the ARPES spectra that partially originates from the momentum-dependent photoemission matrix element. The momentum- and excitation energy dependence of the anomalous high-energy dispersion, termed "waterfalls", is covered in full detail. Finally, the work describes the relation of ARPES with other experimental methods, such as INS spectroscopy. For the optimally doped bilayer Bi-based cuprate, the renormalized two-particle correlation function in the superconducting state is calculated from ARPES data within an itinerant model based on the random phase approximation (RPA). Additionally, two other applications of the same approach are briefly sketched: the relation of ARPES to FT-STS, and the nesting properties of Fermi surfaces in two-dimensional charge density wave compounds.