Van Hove singularity in the magnon spectrum of the antiferromagnetic quantum honeycomb lattice.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33420023.
- Also identified by DOI 10.1038/s41467-020-20335-5 and PMC identifier 7794317.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
In quantum magnets, magnetic moments fluctuate heavily and are strongly entangled with each other, a fundamental distinction from classical magnetism. Here, with inelastic neutron scattering measurements, we probe the spin correlations of the honeycomb lattice quantum magnet YbCl<sub>3</sub>. A linear spin wave theory with a single Heisenberg interaction on the honeycomb lattice, including both transverse and longitudinal channels of the neutron response, reproduces all of the key features in the spectrum. In particular, we identify a Van Hove singularity, a clearly observable sharp feature within a continuum response. The demonstration of such a Van Hove singularity in a two-magnon continuum is important as a confirmation of broadly held notions of continua in quantum magnetism and additionally because analogous features in two-spinon continua could be used to distinguish quantum spin liquids from merely disordered systems. These results establish YbCl<sub>3</sub> as a benchmark material for quantum magnetism on the honeycomb lattice.