1. Antiferromagnetic Excitonic Insulator State in Sr3Ir2O7
- Author
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Mazzone, D. G., Shen, Y., Suwa, H., Fabbris, G., Yang, J., Zhang, S-S., Miao, H., Sears, J., Jia, Ke, Shi, Y. G., Upton, M. H., Casa, D. M., Liu, X., Liu, J., Batista, C. D., and Dean, M. P. M.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
Excitonic insulators are usually considered to form via the condensation of a soft charge mode of bound electron-hole pairs. This, however, presumes that the soft exciton is of spin-singlet character. Early theoretical considerations have also predicted a very distinct scenario, in which the condensation of magnetic excitons results in an antiferromagnetic excitonic insulator state. Here we report resonant inelastic x-ray scattering (RIXS) measurements of Sr3Ir2O7. By isolating the longitudinal component of the spectra, we identify a magnetic mode that is well-defined at the magnetic and structural Brillouin zone centers, but which merges with the electronic continuum in between these high-symmetry points and which decays upon heating concurrent with a decrease in the material's resistivity. We show that a bilayer Hubbard model, in which electron-hole pairs are bound by exchange interactions, consistently explains all the electronic and magnetic properties of Sr3Ir2O7 indicating that this material is a realization of the long-predicted antiferromagnetic excitonic insulators phase., Comment: accepted in Nature Communications; 6 pages main materials
- Published
- 2022
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