Hund’s flat band in a frustrated spinel oxide
Abstract
Electronic flat bands associated with quenched kinetic energy and heavy electron mass have attracted great interest for promoting strong electronic correlations and emergent phenomena such as high-temperature charge fractionalization and superconductivity. Intense experimental and theoretical research has been devoted to establishing the rich nontrivial metallic and heavy fermion phases intertwined with such localized electronic states. Here, we investigate the transition metal oxide spinel LiV 2 O 4 , an enigmatic heavy fermion compound lacking localized f orbital states. We use angle-resolved photoemission spectroscopy and dynamical mean-field theory to reveal a kind of correlation-induced flat band with suppressed interatomic electron hopping arising from intra-atomic Hund’s coupling. The appearance of heavy quasiparticles is ascribed to a proximate orbital-selective Mott state characterized by fluctuating local moments as evidenced by complementary magnetotransport measurements. The spectroscopic fingerprints of long-lived quasiparticles and their disappearance with increasing temperature further support the emergence of a high-temperature “bad” metal state observed in transport data. This work resolves a long-standing puzzle on the origin of heavy fermion behavior and unconventional transport in LiV 2 O 4 . Simultaneously, it opens a path to achieving flat bands through electronic interactions in d -orbital systems with geometrical frustration, potentially enabling the realization of exotic phases of matter such as the fractionalized Fermi liquids.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (29)
Dongjin Oh
Department of Physics, Massachusetts Institute of Technology
Alexander Hampel
Center for Computational Quantum Physics, Flatiron Institute
Joshua P. Wakefield
Peter C. Moen
Department of Physics and Astronomy, University of British Columbia
Steef Smit
Department of Physics and Astronomy, University of British Columbia
Xiangyu Luo
Department of Physics, Massachusetts Institute of Technology
Marta Zonno
Canadian Light Source, Inc., 44 Innovation Boulevard
Sergey Gorovikov
Canadian Light Source, Inc., 44 Innovation Boulevard
Mats Leandersson
Max IV Laboratory, Lund University
Craig Polley
Max IV Laboratory, Lund University
Asish K. Kundu
National Synchrotron Light Source II
Anil Rajapitamahuni
National Synchrotron Light Source II, Brookhaven National Laboratory
Elio Vescovo
National Synchrotron Light Source II
Chris Jozwiak
Advanced Light Source, Lawrence Berkeley National Laboratory
Aaron Bostwick
Advanced Light Source, Lawrence Berkeley National Laboratory
Eli Rotenberg
Advanced Light Source, Lawrence Berkeley National Laboratory
Masahiko Isobe
Max Planck Institute for Solid State Research
Manish Verma
Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg
Matteo Crispino
Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg
Martin Grundner
Department of Physics and Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München
Fabian B. Kugler
Center for Computational Quantum Physics, Flatiron Institute
Olivier Parcollet
Center for Computational Quantum Physics, Flatiron Institute
Ulrich Schollwöck
Department of Physics and Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München
Hidenori Takagi
Max Planck Institute for Solid State Research
Andrea Damascelli
Department of Physics and Astronomy, University of British Columbia
Giorgio Sangiovanni
Joseph G. Checkelsky
Antoine Georges
Center for Computational Quantum Physics, Flatiron Institute
Riccardo Comin