Speaker
Description
The diverse phenomena associated with high-temperature superconductivity in the cuprates present a long-standing theoretical challenge. Various emerging phases have been thoroughly studied experimentally, including angle-resolved photoemission (ARPES), scanning tunnelling microscopy (STM), transport and thermodynamic measurements, but a complete theoretical understanding is still lacking. Many theoretical models have been proposed to describe the pseudogap regime of the cuprate superconductors. Some of them assume that the pseudogap is a precursor to some ordered phase, such as a spin density wave (SDW), or a charge density wave (CDW), or a pair density wave (PDW). A different class of models assume that the pseudogap is a distinct phase of matter characterized by spin liquid physics, which likely undergoes a confinement crossover to a more conventional broken symmetry phase at low temperatures. Here, we will investigate a model in the latter class, which describes the pseudogap metal as a fractionalized Fermi liquid (FL): a state which has electronic quasiparticles around a Luttinger-rule violating small Fermi surface along with neutral spinon excitations. We will show how using a recently introduced 'ancilla' theory of FL phases in a single band model yields simple models which can be successfully compared to a wide range of ARPES experiments in Bi2212 and Bi2201 in both the nodal and anti-nodal regions of the Brillouin zone.
