The National Society of Black Physicists (NSBP) is pleased to present Dr. Philip Phillips as the next speaker for the NSBP ‘Innovate Seminar Series’! The Innovate Seminar Series is a new forum for NSBP members to share their research ideas and projects in a non-specialist way. Professor Phillips is a theoretical condensed matter physicist at the University of Illinois Urbana-Champaign who has an international reputation for his work on transport in disordered and strongly correlated low-dimensional systems.
High-temperature superconductivity in the cuprates remains an unsolved problem because the cuprates start off their lives as Mott insulators in which no organizing principle such a Fermi surface can be invoked to treat the electron interactions. Consequently, it would be advantageous to solve even a toy model that exhibits both Mottness and superconductivity. In 1992 Hatsugai and Khomoto wrote down a momentum-space model for a Mott insulator which is safe to say was largely overlooked, their paper garnering just 21 citations (6 due to our group). I will show exactly that this model when appended with a weak pairing interaction exhibits not only the analogue of Cooper's instability but also a superconducting ground state, thereby demonstrating that a model for a doped Mott insulator can exhibit superconductivity. The properties of the superconducting state differ drastically from that of the standard BCS theory. The elementary excitations of this superconductor are not linear combinations of particle and hole states but rather superpositions of doublons and holons, composite excitations signaling that the superconducting ground state of the doped Mott insulator inherits the non-Fermi liquid character of the normal state.
Additional unexpected features of this model are that it exhibits a superconductivity-induced transfer of spectral weight from high to low energies and a suppression of the superfluid density as seen in the cuprates.
View the talk below and download a PDF version of the talk here.