Multiple quantum phase transitions of different nature in the topological kagome magnet Co&lt;sub&gt;3&lt;/sub&gt;Sn&lt;sub&gt;2-&lt;em&gt;x&lt;/em&gt;&lt;/sub&gt;In&lt;em&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/em&gt;S&lt;sub&gt;2&lt;/sub&gt;

Guguchia, Z.; Zhou, H.; Wang, C.N.; Yin, J.-X.; Mielke III, C.; Tsirkin, S.S.; Belopolski, I.; Zhang, S.-S.; Cochran, T.A.; Neupert, T.; Khasanov, R.; Amato, A.; Jia, S.; Hasan, M.Z.; Luetkens, H.

doi:10.1038/s41535-021-00352-3

Multiple quantum phase transitions of different nature in the topological kagome magnet Co₃Sn_2-xIn_xS₂

Guguchia Z, Zhou H, Wang CN, Yin J-X, Mielke III C, Tsirkin SS, Belopolski I, Zhang S-S, Cochran TA, Neupert T, Khasanov R, Amato A, Jia S, Hasan MZ & Luetkens H

Citation

Guguchia, Z., Zhou, H., Wang, C. N., Yin, J. X., Mielke III, C., Tsirkin, S. S., … Luetkens, H. (2021). Multiple quantum phase transitions of different nature in the topological kagome magnet Co₃Sn_2-xIn_xS₂. npj Quantum Materials, 6, 50 (8 pp.). https://doi.org/10.1038/s41535-021-00352-3

Persistent URL https://www.dora.lib4ri.ch/psi/islandora/object/psi:37880

The exploration of topological electronic phases that result from strong electronic correlations is a frontier in condensed matter physics. One class of systems that is currently emerging as a platform for such studies are so-called kagome magnets based on transition metals. Using muon spin-rotation, we explore magnetic correlations in the kagome magnet Co₃Sn_2-xIn_xS₂ as a function of In-doping, providing putative evidence for an intriguing incommensurate helimagnetic (HM) state. Our results show that, while the undoped sample exhibits an out-of-plane ferromagnetic (FM) ground state, at 5% of In-doping the system enters a state in which FM and in-plane antiferromagnetic (AFM) phases coexist. At higher doping, a HM state emerges and becomes dominant at the critical doping level of only x_cr,1 ≃ 0.3. This indicates a zero temperature first order quantum phase transition from the FM, through a mixed state, to a helical phase at x_cr,1. In addition, at x_cr,2 ≃ 1, a zero temperature second order phase transition from helical to paramagnetic phase is observed, evidencing a HM quantum critical point (QCP) in the phase diagram of the topological magnet Co₃Sn_2-xIn_xS₂. The observed diversity of interactions in the magnetic kagome lattice drives non-monotonous variations of the topological Hall response of this system.