Rise and Fall of Landau's Quasiparticles While Approaching the Mott Transition

• Published in: arXiv.org
• Main Authors: Pustogow, Andrej, Saito, Yohei, Löhle, Anja, Miriam Sanz Alonso, Kawamoto, Atsushi, Dobrosavljević, Vladimir, Dressel, Martin, Fratini, Simone
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 18.01.2021
• Subjects: Elastic scattering; Electron transport; Elementary excitations; Low temperature; Metals; Physics - Strongly Correlated Electrons; Unconventional superconductors
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2101.07201

Landau suggested that the low-temperature properties of metals can be understood in terms of long-lived quasiparticles with all complex interactions included in Fermi-liquid parameters, such as the effective mass \(m^{\star}\). Despite its wide applicability, electronic transport in bad or strange metals and unconventional superconductors is controversially discussed towards a possible collapse of the quasiparticle concept. Here we explore the electrodynamic response of correlated metals at half filling for varying correlation strength upon approaching a Mott insulator. We reveal persistent Fermi-liquid behavior with pronounced quadratic dependences of the optical scattering rate on temperature and frequency, along with a puzzling elastic contribution to relaxation. The strong increase of the resistivity beyond the Ioffe-Regel-Mott limit is accompanied by a `displaced Drude peak' in the optical conductivity. Our results, supported by a theoretical model for the optical response, demonstrate the emergence of a bad metal from resilient quasiparticles that are subject to dynamical localization and dissolve near the Mott transition.