Multiple spin-orbit excitons and the electronic structure of alpha-RuCl3Show others and affiliations
2020 (English)In: Physical Review Research, E-ISSN 2643-1564, Vol. 2, no 4, article id 042007Article in journal (Refereed) Published
Abstract [en]
The honeycomb compound alpha-RuCl3 is widely discussed as a proximate Kitaev spin-liquid material. This scenario builds on spin-orbit entangled j = 1/2 moments arising for a t(2g)(5) electron configuration with strong spin-orbit coupling lambda and a large cubic crystal field. The actual low-energy electronic structure of alpha-RuCl3, however, is still puzzling. In particular, infrared absorption features at 0.30, 0.53, and 0.75 eV seem to be at odds with a j = 1/2 scenario. Also the energy of the spin-orbit exciton, the excitation from j = 1/2 to 3/2, and thus the value of lambda, are controversial. Combining infrared and Raman data, we show that the infrared features can be attributed to single, double, and triple spin-orbit excitons. We find lambda = 0.16 eV and Delta = 42(4) meV for the observed noncubic crystal-field splitting, supporting the validity of the j = 1/2 picture for alpha-RuCl3. The unusual strength of the double excitation is related to the underlying hopping interactions, which form the basis for dominant Kitaev exchange.
Place, publisher, year, edition, pages
American Physical Society (APS) , 2020. Vol. 2, no 4, article id 042007
National Category
Physical Sciences
Identifiers
URN: urn:nbn:se:kth:diva-289507DOI: 10.1103/PhysRevResearch.2.042007ISI: 000605393000001Scopus ID: 2-s2.0-85097581775OAI: oai:DiVA.org:kth-289507DiVA, id: diva2:1524922
Note
QC 20210202
2021-02-022021-02-022022-12-19Bibliographically approved