Momentum-resolved fingerprint of Mottness in layer-dimerized Nb3Br8
Crystalline solids can become band insulators due to fully filled bands, or Mott insulators due to strong electronic correlations. While Mott insulators can theoretically occur in systems with an even number of electrons per unit cell, distinguishing them from band insulators experimentally has remained a longstanding challenge. In this work, we present a unique momentum-resolved signature of a dimerized Mott-insulating phase in the experimental spectral function of Nb<sub>3</sub>Br<sub>8</sub>: the top of the highest occupied band along the out-of-plane direction k<sub>z</sub> has a momentum-space separation Δk<sub>z</sub> = 2π/d, whereas that of a band insulator is less than π/d, where d is the average interlayer spacing. Identifying Nb<sub>3</sub>Br<sub>8</sub> as a Mott insulator is crucial to understand its role in the field-free Josephson diode effect. Moreover, our method could be extended to other van der Waals systems where tuning interlayer coupling and Coulomb interactions can drive a band- to Mott-insulating transition.
Authors
- Francesco Petocchi (ORCID: https://orcid.org/0000-0002-8580-781X)
- Vladimir N. Strocov (ORCID: https://orcid.org/0000-0002-1147-8486)
- Sailong Ju
- Vicky Hasse
- Jiho Yoon (ORCID: https://orcid.org/0000-0002-1412-7227)
- Yun Yen (ORCID: https://orcid.org/0000-0003-1290-7390)
- Mazhar N. Ali (ORCID: https://orcid.org/0000-0002-1129-6105)
- Mihir Date (ORCID: https://orcid.org/0000-0002-9778-6104)
- S. Parkin (ORCID: https://orcid.org/0000-0003-4702-6139)
- Michael Schüler (ORCID: https://orcid.org/0000-0001-7322-6367)
- Matthew D. Watson (ORCID: https://orcid.org/0000-0002-0737-2814)
- Banabir Pal (ORCID: https://orcid.org/0000-0003-2423-4373)
- Niels B. M. Schröter (ORCID: https://orcid.org/0000-0001-6159-4576)
- Yuanfeng Xu (ORCID: https://orcid.org/0000-0002-1390-2308)
- Chris Körner (ORCID: https://orcid.org/0000-0002-9867-0402)
- N. C. Plumb (ORCID: https://orcid.org/0000-0002-2334-8494)
- Emily C. McFarlane (ORCID: https://orcid.org/0000-0002-9863-0187)
- Claudia Felser (ORCID: https://orcid.org/0000-0002-8200-2063)
- Philipp Werner (ORCID: https://orcid.org/0000-0002-2136-6568)
- Georg Woltersdorf (ORCID: https://orcid.org/0000-0001-9299-8880)
- Michael A. Sentef (ORCID: https://orcid.org/0000-0002-7946-0282)
- Jonas A. Krieger (ORCID: https://orcid.org/0000-0003-3337-5530)
- Ilya Kostanovski (ORCID: https://orcid.org/0009-0007-4551-1719)
Institutions
- University of Geneva (CH)
- University of Fribourg (CH)
- Universität Hamburg (DE)
- University of Bremen (DE)
- Paul Scherrer Institute (CH)
- Diamond Light Source (GB)
- Max Planck Institute of Microstructure Physics (DE)
- Max Planck Institute for Chemical Physics of Solids (DE)
- Institute for Applied Systems Technology Bremen (DE)
- Center for Free-Electron Laser Science (DE)
- Max Planck Institute for the Structure and Dynamics of Matter (DE)
- École Polytechnique Fédérale de Lausanne (CH)
- Martin Luther University Halle-Wittenberg (DE)
- Zhejiang University (CN)
- Delft University of Technology (NL)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-04-29
- DOI
- https://doi.org/10.1038/s41467-025-58885-1
- Citations
- 3
- Primary Topic
- Physics of Superconductivity and Magnetism
- Type
- article
- Field-Weighted Citation Impact
- 3.77
Funders
- National Science Foundation
- Diamond Light Source
- European Commission
- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
- National Natural Science Foundation of China