Quantum Criticality in a Strongly Coupled <i>S</i>=1 Spin Chain System at Ambient Field and Pressure

ORAL

Abstract

We report spontaneous appearance of antiferromagnetic order in a model gapped quantum paramagnet Ni(Cl1-xBrx)2-4SC(NH2)2 induced by a change in bromine concentration x. The linear soft-mode spin waves, as well as magnetic Bragg peaks are observed directly in a Br-rich material [1]. Comparison with the preceding studies on specimen with lower bromine concentration [2,3] allows us to reconstruct the overall phase diagram. The transition is qualitatively similar to a z=1 magnetic quantum critical point. However, the observed critical scaling of thermodynamic and magnetic properties has rather unusual critical exponents.

[1] K. Yu. Povarov, A. Mannig et al., Phys. Rev. B 96, 140414R (2017)
[2] K. Yu. Povarov, E. Wulf et al., Phys. Rev. B 92, 024429 (2015)
[3] E. Wulf, D. Hüvonen et al., Phys. Rev. B 88, 174418 (2013)

*This work was supported by the Swiss National Science Foundation, Division II.

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Presenters

  • Kirill Povarov

    • Laboratory for Solid State Physics, ETH Zürich

Authors

  • Kirill Povarov

    • Laboratory for Solid State Physics, ETH Zürich

  • Alexandra Mannig

    • Laboratory for Solid State Physics, ETH Zürich

  • Gerard Perren

    • Laboratory for Solid State Physics, ETH Zürich

  • Johannes Möller

    • Laboratory for Solid State Physics, ETH Zürich

  • Erik Wulf

    • Laboratory for Solid State Physics, ETH Zürich

  • Jacques Ollivier

    • Institut Laue-Langevin

  • Andrey Zheludev

    • Laboratory for Solid State Physics, ETH Zürich