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Planar thermal Hall effect from phonons in a Kitaev candidate material

ORAL

Abstract

Kitaev materials are a promising platform for the realization of quantum spin liquid states. The thermal Hall effect has emerged as a potential probe of exotic excitations within such states. In the Kitaev material α-RuCl3, however, the thermal Hall conductivity κxy has been attributed not only to exotic Majorana fermions [1,2] or chiral magnons [3], but also to phonons [4]. It has been shown theoretically that the former two types of heat carriers can generate a “planar” thermal Hall effect [5-7], whereby the magnetic field is parallel to the heat current, as observed experimentally [3,8], but it is unknown whether phonons also could. Here we show that a planar thermal Hall effect is present in another Kitaev material, Na2Co2TeO6. On the basis of a striking similarity between the temperature and field dependence of κxy and that of the phonon-dominated thermal conductivity κxx, we argue that the planar thermal Hall effect in Na2Co2TeO6 is generated by phonons.

[1] Kasahara, Y. et al. Majorana quantization and half-integer thermal quantum Hall effect in a Kitaev spin liquid. Nature 559, 227-231 (2018).

[2] Bruin, J. A. N. et al. Robustness of the thermal Hall effect close to half-quantization in α-RuCl3. Nat. Phys. 18, 401–405 (2022).

[3] Czajka, P. et al. The planar thermal Hall conductivity in the Kitaev magnet α-RuCl3. arXiv:2201.07873 (2022).

[4] Lefranc¸ois, E. et al. Evidence of a phonon Hall effect in the Kitaev spin liquid candidate α-RuCl3. Phys. Rev. X. 12, 021025 (2022).

[5] Nasu, J. et al. Thermal transport in the Kitaev model. Phys. Rev. Lett. 119, 127204 (2017).

[6] Li, E. C. et al. Sign structure of thermal Hall conductivity and topological magnons for in-plane field polarized Kitaev magnets. Phys. Rev. Lett. 126, 147201 (2021).

[7] Zhang, E. Z. et al. Topological magnons for thermal Hall transport in frustrated magnets with bond-dependent interactions. Phys. Rev. B 103, 174402 (2021).

[8] Yokoi, T. et al. Half-integer quantized anomalous thermal Hall effect in the Kitaev material candidate α-RuCl3. Science 373, 568-572 (2021).

Publication: Lu Chen, Étienne Lefrançois, Ashvini Vallipuram, Quentin Barthélemy, Amir Ataei, Weiliang Yao, Yuan Li, and Louis Taillefer, "Planar thermal Hall effect from phonons in a Kitaev material", plan to submit

Presenters

  • Lu Chen

    Université de Sherbrooke

Authors

  • Lu Chen

    Université de Sherbrooke

  • Etienne Lefrancois

    Universite de Sherbrooke, Université de Sherbrooke

  • Ashvini Vallipuram

    Universite de Sherbrooke

  • Quentin Barthélemy

    Universite de Sherbrooke, Université de Sherbrooke

  • Amirreza Ataei

    Universite de Sherbrooke

  • Weiliang Yao

    Peking Univ

  • Yuan Li

    Peking Univ

  • Louis Taillefer

    Universite de Sherbrooke, Université de Sherbrooke