Analysis of resonant inelastic x-ray scattering from Sr2IrO4 in an itinerant-electron approach

作者：Igarashi Jun ichi^*; Nagao Tatsuya

来源：Physical Review B, 2014, 90(6): 064402.

DOI：10.1103/PhysRevB.90.064402

We analyze the resonant x-ray scattering (RIXS) spectra from Sr2IrO4 in an itinerant-electron approach. Employing a multiorbital tight-binding model on the square lattice, we calculate the one-electron energy band within the Hartree-Fock approximation, which leads to an antiferromagnetic ground state. We then evaluate the two-particle Green%26apos;s functions for the particle-hole pair excitations within the random phase approximation, which are connected to the RIXS spectra within the fast collision approximation. The calculated RIXS spectra exhibit a two-peak structure with slightly different energies in the low-energy region, which originate from the bound states in the two-particle Green%26apos;s function. They may be interpreted as the split modes of a magnon. We also obtain several delta-function peaks, which arise from the bound states around the bottom of the energy continuum. They may be called exciton modes. These characteristics are in qualitative agreement with the RIXS experiment, demonstrating that the weak coupling theory could explain both the magnon and the exciton peaks in the RIXS spectra on an equal footing.

• 出版日期2014-8-5