Fermi arcs in an exactly solvable model for cuprates

Abstract

In the search for room-temperature superconductors, understanding the pseudogap phase in strange metals such as cuprates is of vital importance for a possible microscopic description of high-temperature superconductivity that exceeds the BCS-theory critical temperature. In this thesis we investigate strongly correlated electron models that can describe disconnected Fermi surfaces known as Fermi arcs. In contrast to the widely used Hubbard model the model we use is exactly solvable, giving an intuitive understanding of what Fermi arcs are. We go into the properties of the Hatsugai-Kohmoto model such as spin correlation and entropy. Then we look at deviations from this model that can describe Fermi arcs exactly. After we first introduce a model that more naturally arises from the Hatsugai-Kohmoto model and supports Fermi arcs we arrive at a recently discovered model that through antiferromagnetic spin coupling on different momenta in the interaction gives a description of Fermi arcs in the nodal direction which agrees which APRES experiments on cuprates. In this model, we find a connected surface that consist of Fermi arcs and Luttinger arcs that enclose multiple ground-states in momentum space.