Ga doping modifies the charge density wave in ScV₆Sn₆

Charge density waves and structural instabilities are becoming a reoccurring theme in the beloved kagome metals. ScV₆Sn₆ is a prominent example, developing a CDW-like modulation on cooling through 92 K. [1] This instability appears to be a consequence of underfill atomic columns [2] and is characterized by a strong competition between distortion modes. [3,4,5,6]

Gallium substitution modifies the band filling and lattice strain in HfFe6Ge6-type materials. We synthesize Ga-doped ScV₆Sn₆ crystals to explore the impact chemical tuning on the structural modulation. Our magnetization and diffraction investigations reveal that Ga-doping dramatically enhances the CDW instability and modifies its character. I will discuss the implications of our observation for the competition between the structural instabilities.

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[2] W. R. Meier, R. P. Madhogaria, S. Mozaffari, et al., Tiny Sc allows the chains to rattle: Impact of Lu and Y doping on the charge density wave in ScV6Sn6. J. Am. Chem. Soc., 145, 38, 20943, (2023) https://doi.org/10.1021/jacs.3c06394

[3] H. Tan and B. Yan, Abundant Lattice Instability in Kagome Metal ScV6Sn6. Phys. Rev. Lett. 130, 266402 (2023) https://doi.org/10.1103/PhysRevLett.130.266402

[4] A. Korshunov, H. Hu, D. Subires, et al. Softening of a flat phonon mode in the kagome ScV6Sn6. Nat. Commun. 14, 6646 (2023). https://doi.org/10.1038/s41467-023-42186-6

[5] S. Cao, C. Xu, H. Fukui, et al. Competing charge-density wave instabilities in the kagome metal ScV6Sn6. Nat. Commun. 14, 7671 (2023). https://doi.org/10.1038/s41467-023-43454-1

[6] G. Pokharel, B. R. Ortiz, L. Kautzsch, et al., Frustrated charge order and cooperative distortions in ScV6Sn6, Phys. Rev. Materials 7, 104201 (2023). https://doi.org/10.1103/PhysRevMaterials.7.104201