Magnon bound states versus anyonic Majorana excitations in the Kitaev honeycomb magnet α-RuCl3

authored by
Dirk Wulferding, Youngsu Choi, Seung Hwan Do, Chan Hyeon Lee, Peter Lemmens, Clément Faugeras, Yann Gallais, Kwang Yong Choi

The pure Kitaev honeycomb model harbors a quantum spin liquid in zero magnetic fields, while applying finite magnetic fields induces a topological spin liquid with non-Abelian anyonic excitations. This latter phase has been much sought after in Kitaev candidate materials, such as α-RuCl3. Currently, two competing scenarios exist for the intermediate field phase of this compound (B = 7 − 10 T), based on experimental as well as theoretical results: (i) conventional multiparticle magnetic excitations of integer quantum number vs. (ii) Majorana fermionic excitations of possibly non-Abelian nature with a fractional quantum number. To discriminate between these scenarios a detailed investigation of excitations over a wide field-temperature phase diagram is essential. Here, we present Raman spectroscopic data revealing low-energy quasiparticles emerging out of a continuum of fractionalized excitations at intermediate fields, which are contrasted by conventional spin-wave excitations. The temperature evolution of these quasiparticles suggests the formation of bound states out of fractionalized excitations.

External Organisation(s)
Technische Universität Braunschweig
Institute for Basic Science
Chung-Ang University
University Grenoble-Alpes (UGA)
Université de Paris
Nature Communications
Publication date
Publication status
Peer reviewed
ASJC Scopus subject areas
Chemistry(all), Biochemistry, Genetics and Molecular Biology(all), Physics and Astronomy(all)
Electronic version(s) (Access: Open)