UC Santa Cruz

In this dissertation, we present Extremely Correlated Fermi Liquid (ECFL) description of low energy excitation spectrum of high temperature cuprate superconductors measured by Angle Resolved Photoemission Spectroscopy (ARPES). Focusing on interpretation of the ARPES data, we propose a rigorous approach to understanding the unconventional quasiparticle dynamics in high Tc cuprate superconductors. First, we present ARPES line shapes fitting with the ECFL theory. The ECFL theory is very successful in explaining the ARPES spectral functions of high Tc cuprate superconductors, and it fits the ARPES line shapes as functions of momentum (momentum distribution curves, MDCs) and energy (energy distribution curves, EDCs) for different materials and different temperature with the same intrinsic physical variables along the nodal direction. Although it is not the first to fit both MDCs and EDCs of high Tc cuprate superconductors, the ECFL theory offers unprecedented applicability in fitting the ARPES spectral functions. Second, the ECFL theory provides a robust discussion for the origin of kinks in energy dispersion of strongly correlated material measured by ARPES. A bending anomaly in the energy dispersion of strongly correlated matter, the universal low energy kink in the ARPES spectrum ~ 50 - 100 meV, can not be explained within the standard linear band dispersion theory because of significant corrections due to interactions. In our work, we address correlation kinks arising from the momentum dependent Dyson self-energy of the ECFL theory. The calculation is overdetermined, and four independent variables can predict sets of measurable relations in the ARPES experiments. We find that ECFL interpretation of the ARPES kinks is consistent with the available experimental data, and we provide a decisive set of predictions for future high resolution ARPES experiments.