Signatures of Weyl Fermion Annihilation in a Correlated Kagome Magnet

Ilya Belopolski, Tyler A. Cochran, Xiaoxiong Liu, Zi-Jia Cheng, Xian P. Yang, Zurab Guguchia, Stepan S. Tsirkin, Jia-Xin Yin, Praveen Vir, Gohil S. Thakur, Songtian S. Zhang, Junyi Zhang, Konstantine Kaznatcheev, Guangming Cheng, Guoqing Chang, Daniel Multer, Nana Shumiya, Maksim Litskevich, Elio Vescovo, Timur K. Kim, Cephise Cacho, Nan Yao, Claudia Felser, Titus Neupert, and M. Zahid Hasan
Phys. Rev. Lett. 127, 256403 – Published 17 December 2021
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Abstract

The manipulation of topological states in quantum matter is an essential pursuit of fundamental physics and next-generation quantum technology. Here we report the magnetic manipulation of Weyl fermions in the kagome spin-orbit semimetal Co3Sn2S2, observed by high-resolution photoemission spectroscopy. We demonstrate the exchange collapse of spin-orbit-gapped ferromagnetic Weyl loops into paramagnetic Dirac loops under suppression of the magnetic order. We further observe that topological Fermi arcs disappear in the paramagnetic phase, suggesting the annihilation of exchange-split Weyl points. Our findings indicate that magnetic exchange collapse naturally drives Weyl fermion annihilation, opening new opportunities for engineering topology under correlated order parameters.

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  • Received 2 September 2021
  • Accepted 12 November 2021

DOI:https://doi.org/10.1103/PhysRevLett.127.256403

© 2021 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Ilya Belopolski1,12,*, Tyler A. Cochran1, Xiaoxiong Liu2, Zi-Jia Cheng1, Xian P. Yang1, Zurab Guguchia1,3, Stepan S. Tsirkin2, Jia-Xin Yin1, Praveen Vir4, Gohil S. Thakur4,5, Songtian S. Zhang1, Junyi Zhang6, Konstantine Kaznatcheev7, Guangming Cheng8, Guoqing Chang9, Daniel Multer1, Nana Shumiya1, Maksim Litskevich1, Elio Vescovo7, Timur K. Kim10, Cephise Cacho10, Nan Yao8, Claudia Felser4, Titus Neupert2, and M. Zahid Hasan1,8,11,†

  • 1Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
  • 2Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
  • 3Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, Villigen PSI, Switzerland
  • 4Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
  • 5Faculty of Chemistry and Food Chemistry, Technische Universitat, 01069 Dresden, Germany
  • 6Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
  • 7National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
  • 8Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, USA
  • 9Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore, Singapore
  • 10Diamond Light Source, Didcot OX11 0DE, United Kingdom
  • 11Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
  • 12RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan

  • *ilya.belopolski@riken.jp
  • mzhasan@princeton.edu

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Issue

Vol. 127, Iss. 25 — 17 December 2021

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