Topological magnonic materials have attracted much interest because of the potential for dissipationless spintronic applications. Pyrochlore iridates are theoretically regarded as good candidates for designing topological magnon bands. However, experimental identification of topological magnon bands in pyrochlore iridates remains elusive. We explored this possibility in Y2Ir2O7 using Raman spectroscopy to measure both the single-magnon excitations and anomalous phonon shifts. From the single-magnon energies and tight-binding model calculations concerning the phonons, we determined the key parameters in the spin Hamiltonian. These confirm that Y2Ir2O7 hosts a nontrivial magnon band topology distinct from other pyrochlore iridate compounds. Our work demonstrates that pyrochlore iridates constitute a system in which the magnon band topology can be tailored and that Raman spectroscopy is a powerful technique to explore magnon band topology.
Bibliographical noteFunding Information:
This work was supported by the Research Center Program of IBS (Institute for Basic Science) in Korea (IBS-R009-D1). Y. Wang is grateful for the support of the Office of Naval Research under Grant No. N00014-20-1-2308, and K. S. Burch acknowledges support from the Air Force Office of Scientific Research under Grant No. FA9550-20-1-0282. I.-S. Y. was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (2017R1A2B2009309). J.-G. P. was supported by the Leading Researcher Program of the National Research Foundation of Korea (Grant No. 2020R1A3B2079375). S. J. M. was supported by the National Research Foundation grant of Korea (NRF) funded by the Korean government (MSIT) (2019R1A2C1084237).
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