抄録
<jats:title>Abstract</jats:title><jats:p>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 Sr<jats:sub>3</jats:sub>Ir<jats:sub>2</jats:sub>O<jats:sub>7</jats:sub>. 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 Sr<jats:sub>3</jats:sub>Ir<jats:sub>2</jats:sub>O<jats:sub>7</jats:sub> indicating that this material is a realization of the long-predicted antiferromagnetic excitonic insulator phase.</jats:p>
収録刊行物
-
- Nature Communications
-
Nature Communications 13 (1), 2022-02-17
Springer Science and Business Media LLC