IDEAS home Printed from https://ideas.repec.org/a/nat/nature/v559y2018i7713d10.1038_s41586-018-0274-0.html
   My bibliography  Save this article

Majorana quantization and half-integer thermal quantum Hall effect in a Kitaev spin liquid

Author

Listed:
  • Y. Kasahara

    (Kyoto University)

  • T. Ohnishi

    (Kyoto University)

  • Y. Mizukami

    (University of Tokyo)

  • O. Tanaka

    (University of Tokyo)

  • Sixiao Ma

    (Kyoto University)

  • K. Sugii

    (Institute for Solid State Physics, University of Tokyo)

  • N. Kurita

    (Tokyo Institute of Technology)

  • H. Tanaka

    (Tokyo Institute of Technology)

  • J. Nasu

    (Tokyo Institute of Technology)

  • Y. Motome

    (University of Tokyo)

  • T. Shibauchi

    (University of Tokyo)

  • Y. Matsuda

    (Kyoto University)

Abstract

The quantum Hall effect in two-dimensional electron gases involves the flow of topologically protected dissipationless charge currents along the edges of a sample. Integer or fractional electrical conductance is associated with edge currents of electrons or quasiparticles with fractional charges, respectively. It has been predicted that quantum Hall phenomena can also be created by edge currents with a fundamentally different origin: the fractionalization of quantum spins. However, such quantization has not yet been observed. Here we report the observation of this type of quantization of the Hall effect in an insulating two-dimensional quantum magnet1, α-RuCl3, with a dominant Kitaev interaction (a bond-dependent Ising-type interaction) on a two-dimensional honeycomb lattice2–7. We find that the application of a magnetic field parallel to the sample destroys long-range magnetic order, leading to a field-induced quantum-spin-liquid ground state with substantial entanglement of local spins8–12. In the low-temperature regime of this state, the two-dimensional thermal Hall conductance reaches a quantum plateau as a function of the applied magnetic field and has a quantization value that is exactly half of the two-dimensional thermal Hall conductance of the integer quantum Hall effect. This half-integer quantization of the thermal Hall conductance in a bulk material is a signature of topologically protected chiral edge currents of charge-neutral Majorana fermions (particles that are their own antiparticles), which have half the degrees of freedom of conventional fermions13–16. These results demonstrate the fractionalization of spins into itinerant Majorana fermions and Z2 fluxes, which is predicted to occur in Kitaev quantum spin liquids1,3. Above a critical magnetic field, the quantization disappears and the thermal Hall conductance goes to zero rapidly, indicating a topological quantum phase transition between the states with and without chiral Majorana edge modes. Emergent Majorana fermions in a quantum magnet are expected to have a great impact on strongly correlated quantum matter, opening up the possibility of topological quantum computing at relatively high temperatures.

Suggested Citation

  • Y. Kasahara & T. Ohnishi & Y. Mizukami & O. Tanaka & Sixiao Ma & K. Sugii & N. Kurita & H. Tanaka & J. Nasu & Y. Motome & T. Shibauchi & Y. Matsuda, 2018. "Majorana quantization and half-integer thermal quantum Hall effect in a Kitaev spin liquid," Nature, Nature, vol. 559(7713), pages 227-231, July.
  • Handle: RePEc:nat:nature:v:559:y:2018:i:7713:d:10.1038_s41586-018-0274-0
    DOI: 10.1038/s41586-018-0274-0
    as

    Download full text from publisher

    File URL: https://www.nature.com/articles/s41586-018-0274-0
    File Function: Abstract
    Download Restriction: Access to the full text of the articles in this series is restricted.

    File URL: https://libkey.io/10.1038/s41586-018-0274-0?utm_source=ideas
    LibKey link: if access is restricted and if your library uses this service, LibKey will redirect you to where you can use your library subscription to access this item
    ---><---

    As the access to this document is restricted, you may want to search for a different version of it.

    Citations

    Citations are extracted by the CitEc Project, subscribe to its RSS feed for this item.
    as


    Cited by:

    1. Hikaru Takeda & Masataka Kawano & Kyo Tamura & Masatoshi Akazawa & Jian Yan & Takeshi Waki & Hiroyuki Nakamura & Kazuki Sato & Yasuo Narumi & Masayuki Hagiwara & Minoru Yamashita & Chisa Hotta, 2024. "Magnon thermal Hall effect via emergent SU(3) flux on the antiferromagnetic skyrmion lattice," Nature Communications, Nature, vol. 15(1), pages 1-8, December.
    2. Xiaokang Li & Yo Machida & Alaska Subedi & Zengwei Zhu & Liang Li & Kamran Behnia, 2023. "The phonon thermal Hall angle in black phosphorus," Nature Communications, Nature, vol. 14(1), pages 1-6, December.
    3. Lu Chen & Étienne Lefrançois & Ashvini Vallipuram & Quentin Barthélemy & Amirreza Ataei & Weiliang Yao & Yuan Li & Louis Taillefer, 2024. "Planar thermal Hall effect from phonons in a Kitaev candidate material," Nature Communications, Nature, vol. 15(1), pages 1-7, December.
    4. G. Cassella & P. d’Ornellas & T. Hodson & W. M. H. Natori & J. Knolle, 2023. "An exact chiral amorphous spin liquid," Nature Communications, Nature, vol. 14(1), pages 1-6, December.
    5. Sebastian Schimmel & Yanina Fasano & Sven Hoffmann & Julia Besproswanny & Laura Teresa Corredor Bohorquez & Joaquín Puig & Bat-Chen Elshalem & Beena Kalisky & Grigory Shipunov & Danny Baumann & Saicha, 2024. "Surface superconductivity in the topological Weyl semimetal t-PtBi2," Nature Communications, Nature, vol. 15(1), pages 1-6, December.
    6. Saurabh Kumar Srivastav & Ravi Kumar & Christian Spånslätt & K. Watanabe & T. Taniguchi & Alexander D. Mirlin & Yuval Gefen & Anindya Das, 2022. "Determination of topological edge quantum numbers of fractional quantum Hall phases by thermal conductance measurements," Nature Communications, Nature, vol. 13(1), pages 1-8, December.
    7. Taiki Uehara & Takumi Ohtsuki & Masafumi Udagawa & Satoru Nakatsuji & Yo Machida, 2022. "Phonon thermal Hall effect in a metallic spin ice," Nature Communications, Nature, vol. 13(1), pages 1-8, December.
    8. Dechen Zhang & Kuan-Wen Chen & Guoxin Zheng & Fanghang Yu & Mengzhu Shi & Yuan Zhu & Aaron Chan & Kaila Jenkins & Jianjun Ying & Ziji Xiang & Xianhui Chen & Lu Li, 2024. "Large oscillatory thermal hall effect in kagome metals," Nature Communications, Nature, vol. 15(1), pages 1-8, December.
    9. Xu-Guang Zhou & Han Li & Yasuhiro H. Matsuda & Akira Matsuo & Wei Li & Nobuyuki Kurita & Gang Su & Koichi Kindo & Hidekazu Tanaka, 2023. "Possible intermediate quantum spin liquid phase in α-RuCl3 under high magnetic fields up to 100 T," Nature Communications, Nature, vol. 14(1), pages 1-7, December.

    More about this item

    Statistics

    Access and download statistics

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:nat:nature:v:559:y:2018:i:7713:d:10.1038_s41586-018-0274-0. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    We have no bibliographic references for this item. You can help adding them by using this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: Sonal Shukla or Springer Nature Abstracting and Indexing (email available below). General contact details of provider: http://www.nature.com .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.