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. KimCephise Cacho, Nan Yao, Claudia Felser, Titus Neupert, M. Zahid Hasan

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

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.

Original languageEnglish (US)
Article number256403
JournalPhysical review letters
Volume127
Issue number25
DOIs
StatePublished - Dec 17 2021

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy

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