Abstract
The charge density wave (CDW), a translational symmetry breaking electronic liquid, plays a pivotal role in correlated quantum materials, such as high-Tc superconductors and topological semimetals. Recently, CDWs that possibly intertwine with superconductivity and magnetism are observed in various kagome metals. However, the nature of CDWs and the role of the Fermi-surface (FS) topology in these materials remain an unresolved challenge. In this paper, we reveal the formation of CDWs in the newly discovered kagome metal LuNb6Sn6. We observe a “yield sign”-like hollow triangular diffuse scattering pattern and nearly complete softening of a flat optical phonon band near QH = (1/3, 1/3, 1/2). The scattering intensity of the diffuse scattering displays divergent behavior as decreasing temperature until TCDW = 70 K, where a competing CDW at QCDW = (1/3, 1/3, 1/3) emerges. Combined with scanning tunneling microscopy/spectroscopy and first-principles calculations, our observations support a Fermi-surface driven frustration that suppresses the leading CDW instability at QH. This frustration is relieved by the emergence of a subleading CDW at QCDW. These results provide insights into the interplay between the Fermi surface, strong electron-phonon coupling, and charge density wave formation in quantum materials.
| Original language | English |
|---|---|
| Article number | 245113 |
| Journal | Physical Review B |
| Volume | 112 |
| Issue number | 24 |
| DOIs | |
| State | Published - Dec 5 2025 |
Funding
We thank Joseph Paddison, Ziqiang Wang, Lingyuan Kong, and Mark Dean for stimulating discussions. This research was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences (DOE-BES), Materials Sciences and Engineering Division (ARPES, X-ray and sample growth). ARPES and X-ray scattering measurements used resources at 21-ID-1, 4-ID, and 10-ID beamlines of the National Synchrotron Light Source II, a U.S. Department of Energy Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory (BNL) under Contract No. DE-SC0012704. W.R.M. and D.M. acknowledge support from the Gordon and Betty Moore Foundation’s EPiQS Initiative, Grant No. GBMF9069 to D.M. J.I. is supported by NSF Career Award No. DMR-2340394. STM measurements were supported by the National Science Foundation under Grant No. DMR-2004691 (X.H.) and by the Scan Probe Microscopy FWP under DOE-BES at BNL (A.N.P).