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Korshunov A, Hu H, Subires D, Jiang Y, Călugăru D, Feng X, Rajapitamahuni A, Yi C, Roychowdhury S, Vergniory MG, Strempfer J, Shekhar C, Vescovo E, Chernyshov D, Said AH, Bosak A, Felser C, Bernevig BA, Blanco-Canosa S. Softening of a flat phonon mode in the kagome ScV 6Sn 6. Nat Commun 2023; 14:6646. [PMID: 37863907 PMCID: PMC10589229 DOI: 10.1038/s41467-023-42186-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 09/29/2023] [Indexed: 10/22/2023] Open
Abstract
Geometrically frustrated kagome lattices are raising as novel platforms to engineer correlated topological electron flat bands that are prominent to electronic instabilities. Here, we demonstrate a phonon softening at the kz = π plane in ScV6Sn6. The low energy longitudinal phonon collapses at ~98 K and q = [Formula: see text] due to the electron-phonon interaction, without the emergence of long-range charge order which sets in at a different propagation vector qCDW = [Formula: see text]. Theoretical calculations corroborate the experimental finding to indicate that the leading instability is located at [Formula: see text] of a rather flat mode. We relate the phonon renormalization to the orbital-resolved susceptibility of the trigonal Sn atoms and explain the approximately flat phonon dispersion. Our data report the first example of the collapse of a kagome bosonic mode and promote the 166 compounds of kagomes as primary candidates to explore correlated flat phonon-topological flat electron physics.
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Affiliation(s)
- A Korshunov
- European Synchrotron Radiation Facility (ESRF), BP 220, F-38043, Grenoble, France
| | - H Hu
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain
| | - D Subires
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain
| | - Y Jiang
- Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - D Călugăru
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - X Feng
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - A Rajapitamahuni
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - C Yi
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - S Roychowdhury
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - M G Vergniory
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - J Strempfer
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - C Shekhar
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - E Vescovo
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - D Chernyshov
- Swiss-Norwegian BeamLines at European Synchrotron Radiation Facility, Grenoble, France
| | - A H Said
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - A Bosak
- European Synchrotron Radiation Facility (ESRF), BP 220, F-38043, Grenoble, France
| | - C Felser
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - B Andrei Bernevig
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain.
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA.
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain.
| | - S Blanco-Canosa
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain.
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain.
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Subires D, Korshunov A, Said AH, Sánchez L, Ortiz BR, Wilson SD, Bosak A, Blanco-Canosa S. Order-disorder charge density wave instability in the kagome metal (Cs,Rb)V 3Sb 5. Nat Commun 2023; 14:1015. [PMID: 36823175 PMCID: PMC9950456 DOI: 10.1038/s41467-023-36668-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 02/06/2023] [Indexed: 02/25/2023] Open
Abstract
The origin of the charge density wave phases in the kagome metal compound AV3Sb5 is still under great scrutiny. Here, we combine diffuse and inelastic x-ray scattering to identify a 3-dimensional precursor of the charge order at the L point that condenses into a CDW through a first order phase transition. The quasi-elastic critical scattering indicates that the dominant contribution to the diffuse precursor is the elastic central peak without phonon softening. However, the inelastic spectra show a small broadening of the Einstein-type phonon mode on approaching TCDW. Our results point to the situation where the Fermi surface instability at the L point is of order-disorder type with critical growth of quasi-static domains. The experimental data indicate that the CDW consists on an alternating Star of David and trihexagonal distortions and its dynamics goes beyond the classical weak-coupling scenario and is discussed within strong-electron phonon coupling and non-adiabatic models.
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Affiliation(s)
- D. Subires
- grid.452382.a0000 0004 1768 3100Donostia International Physics Center (DIPC), San Sebastián, Spain
| | - A. Korshunov
- grid.5398.70000 0004 0641 6373European Synchrotron Radiation Facility (ESRF), BP 220, F-38043 Grenoble Cedex, France
| | - A. H. Said
- grid.187073.a0000 0001 1939 4845Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439 USA
| | - L. Sánchez
- grid.452382.a0000 0004 1768 3100Donostia International Physics Center (DIPC), San Sebastián, Spain
| | - Brenden R. Ortiz
- grid.133342.40000 0004 1936 9676Materials Department and California Nanosystems Institute, university of California Santa Barbara, Santa Barbara, CA 93106 USA
| | - Stephen D. Wilson
- grid.133342.40000 0004 1936 9676Materials Department and California Nanosystems Institute, university of California Santa Barbara, Santa Barbara, CA 93106 USA
| | - A. Bosak
- grid.5398.70000 0004 0641 6373European Synchrotron Radiation Facility (ESRF), BP 220, F-38043 Grenoble Cedex, France
| | - S. Blanco-Canosa
- grid.452382.a0000 0004 1768 3100Donostia International Physics Center (DIPC), San Sebastián, Spain ,grid.424810.b0000 0004 0467 2314IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
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