Electronic Structure of Rare-Earth Nickelates from First-Principles

This thesis demonstrates the value of theoretical approaches in the discovery of new superconducting materials. It reports a detailed study of the recently discovered nickel-oxide (nickelate) superconductors using multiple first-principles computational tools, from density functional theory to dynamical mean field theory. In the context of superconductivity, discoveries have generally been linked to serendipitous experimental discovery; this thesis reports some of the few examples of predictions of new superconductors that have later been realized in practice, a prime example of the significance of the methodology it expounds. Overall, it represents a seminal systematic work in the electronic structure theory of the emergent field of nickelate superconductivity.

Chapter 1: Introduction.- Chapter 2: Ab-initio Approaches to Correlated Materials.- Chapter 3: Dft Trends In The Electronic Structure and Magnetic Properties of Reduced Ruddlesden-popper Nickelates.- Chapter 4: Comparing Layered Nickelate Superconductors Within Dft+Dmft.- Chapter 5: Many-body Trends of Reduced Ruddlesden-popper Nickelates.- Chapter 6: Conductivity of Infinite-layer Nickelate As A Probe of Spectator Bands.- Chapter 7: Summary and Outlook.

Harrison LaBollita is a computational condensed matter physicist whose research focuses on the electronic structure of strongly correlated materials. He obtained his PhD in Physics at Arizona State University under the supervision of Prof. Antia S. Botana, where he focused on superconductivity in nickel-oxides (nickelates). Harrison will continue researching strongly correlated materials as a postdoctoral fellow at the Flatiron Institute, a division of the Simons Foundation, in the fall of 2024.