Accessing bands with extended quantum metric in kagome Cs <sub>2</sub> Ni <sub>3</sub> S <sub>4</sub> through soft chemical processing
Flat bands that do not merely arise from weak interactions can produce exotic physical properties, such as superconductivity or correlated many-body effects. The quantum metric can differentiate whether flat bands will result in correlated physics or are merely dangling bonds. A potential avenue for achieving correlated flat bands involves leveraging geometrical constraints within specific lattice structures, such as the kagome lattice; however, materials are often more complex. In these cases, quantum geometry becomes a powerful indicator of the nature of bands with small dispersions. We present a simple, soft-chemical processing route to access a flat band with an extended quantum metric below the Fermi level. By oxidizing Ni-kagome material Cs<sub>2</sub>Ni<sub>3</sub>S<sub>4</sub> to CsNi<sub>3</sub>S<sub>4</sub>, we see a two orders of magnitude drop in the room temperature resistance. However, CsNi<sub>3</sub>S<sub>4</sub> is still insulating, with no evidence of a phase transition. Using experimental data, density functional theory calculations, and symmetry analysis, our results suggest the emergence of a correlated insulating state of unknown origin.
Authors
- Jaime M. Moya (ORCID: https://orcid.org/0000-0003-1241-9493)
- Connor J. Pollak
- Dumitru Călugăru (ORCID: https://orcid.org/0000-0002-5897-9878)
- Haoyu Hu (ORCID: https://orcid.org/0000-0002-3787-6634)
- Leslie Mareike Schoop (ORCID: https://orcid.org/0000-0003-3459-4241)
- Yi Jiang (ORCID: https://orcid.org/0000-0003-1543-0284)
- Bogdan Andrei Bernevig (ORCID: https://orcid.org/0000-0001-6337-4024)
- Ratnadwip Singha (ORCID: https://orcid.org/0000-0002-3155-2137)
- Jason F. Khoury (ORCID: https://orcid.org/0000-0003-4769-6730)
- Graciela Villalpando (ORCID: https://orcid.org/0009-0007-2146-0240)
- Birender Singh (ORCID: https://orcid.org/0000-0002-9640-0070)
- Milena Jovanović (ORCID: https://orcid.org/0000-0002-0185-0184)
- Vincent Plisson (ORCID: https://orcid.org/0000-0003-4535-8906)
- Fang Yuan (ORCID: https://orcid.org/0000-0001-7286-3233)
- Brianna L. Hoff (ORCID: https://orcid.org/0000-0002-1971-8931)
- Stephanie Dulovic (ORCID: https://orcid.org/0000-0003-0921-9714)
- Kenneth S. Burch (ORCID: https://orcid.org/0000-0002-7541-0245)
- Nitish Mathur (ORCID: https://orcid.org/0000-0003-1614-3375)
Institutions
- Boston College (US)
- Ikerbasque (ES)
- Indian Institute of Technology Guwahati (IN)
- North Carolina State University (US)
- Princeton University (US)
- Donostia International Physics Center (ES)
- Arizona State University (US)
Publication Details
- Journal
- Science Advances
- Published
- 2024-09-20
- DOI
- https://doi.org/10.1126/sciadv.adl1103
- Citations
- 6
- Primary Topic
- Advanced Condensed Matter Physics
- Type
- article
- Field-Weighted Citation Impact
- 1.87