Quantum criticality in Sc(V<sub>1-x</sub>Cr<sub>x</sub>)<sub>6</sub>Sn<sub>6</sub> ?

ORAL

Abstract

High-resolution thermal-expansion and heat-capacity measurements are combined to study the influence of chromium substitution on single crystals of the bi-layered Kagome metal ScV6Sn6. Similar to CsV3Sb5 [1], here we report that the charge-density wave (CDW) in ScV6Sn6 exhibits a colossal response to c-axis stress and no evidence for in-plane rotational symmetry breaking. The CDW is completely suppressed for xcr ≈ 6%, where a significant enhancement of the Sommerfeld coefficient is found. A sign change of the Grüneisen parameter, a smoking gun of quantum phase transitions [2], is observed near this concentration. Further, the disappearance of the CDW is accompanied by the softening of an acoustic phonon mode and the emergence of a low-lying energy optical mode. A comparison of our results with hydrostatic-pressure measurements is made.

[1] M. Frachet et al., Phys. Rev. Lett. 132, 186001 (2024).

[2] M. Garst and A. Rosch, Phys. Rev. B 72, 205129 (2005).

*This work was partially funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) TRR 288-422213477 (Projects No. A02 and No. B03) and Chinesisch-Deutsche Mobilitätsprogamm of Chinesisch-Deutsche Zentrum für Wissenschaftsförderung (Grant No. M-0496).

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Presenters

  • Frédéric Hardy

    • Karlsruhe Institute of Technology
    • Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology

Authors

  • Frédéric Hardy

    • Karlsruhe Institute of Technology
    • Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology

  • Liran Wang

    • Karlsruhe Institute of Technology
    • Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology

  • Xinrun Mi

    • Chongqing University
    • Low Temperature Physics Lab, College of Physics & Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, People's Republic of China

  • Xintong Chen

    • Chongqing University,
    • Low Temperature Physics Lab, College of Physics & Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, People's Republic of China

  • Nour Maraytta

    • Karlsruhe Institute of Technology

  • Michael Merz

    • Karlsruhe Institute of Technology
    • Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany

  • Aifeng Wang

    • Chongqing University
    • Low Temperature Physics Lab, College of Physics & Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, People's Republic of China

  • Yisheng Chai

    • Chongqing University

  • Mingquan He

    • Chongqing University
    • Low Temperature Physics Lab, College of Physics & Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, People's Republic of China

  • Christoph Meingast

    • Karlsruhe Institute of Technology
    • Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology