Hund’s flat band in a frustrated spinel oxide
(2025) In Proceedings of the National Academy of Sciences of the United States of America 122(45).- 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 LiV2O4, 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... (More)
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 LiV2O4, 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 LiV2O4. 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.
(Less)
- author
- organization
- publishing date
- 2025-11-11
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- flat band, frustrated lattice, heavy fermion transition metal compound, Hund’s coupling
- in
- Proceedings of the National Academy of Sciences of the United States of America
- volume
- 122
- issue
- 45
- article number
- e2518213122
- publisher
- National Academy of Sciences
- external identifiers
-
- scopus:105021069324
- pmid:41196354
- ISSN
- 0027-8424
- DOI
- 10.1073/pnas.2518213122
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: Copyright © 2025 the Author(s).
- id
- 22c92628-9aa6-492b-830b-95b5a954a29e
- date added to LUP
- 2025-12-11 10:15:33
- date last changed
- 2025-12-12 03:00:19
@article{22c92628-9aa6-492b-830b-95b5a954a29e,
abstract = {{<p>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<sub>2</sub>O<sub>4</sub>, 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<sub>2</sub>O<sub>4</sub>. 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.</p>}},
author = {{Oh, Dongjin and Hampel, Alexander and Wakefield, Joshua P. and Moen, Peter C. and Smit, Steef and Luo, Xiangyu and Zonno, Marta and Gorovikov, Sergey and Leandersson, Mats and Polley, Craig and Kundu, Asish K. and Rajapitamahuni, Anil and Vescovo, Elio and Jozwiak, Chris and Bostwick, Aaron and Rotenberg, Eli and Isobe, Masahiko and Verma, Manish and Crispino, Matteo and Grundner, Martin and Kugler, Fabian B. and Parcollet, Olivier and Schollwöck, Ulrich and Takagi, Hidenori and Damascelli, Andrea and Sangiovanni, Giorgio and Checkelsky, Joseph G. and Georges, Antoine and Comin, Riccardo}},
issn = {{0027-8424}},
keywords = {{flat band; frustrated lattice; heavy fermion transition metal compound; Hund’s coupling}},
language = {{eng}},
month = {{11}},
number = {{45}},
publisher = {{National Academy of Sciences}},
series = {{Proceedings of the National Academy of Sciences of the United States of America}},
title = {{Hund’s flat band in a frustrated spinel oxide}},
url = {{http://dx.doi.org/10.1073/pnas.2518213122}},
doi = {{10.1073/pnas.2518213122}},
volume = {{122}},
year = {{2025}},
}