English

Resonant inelastic x-ray scattering spectra in the hyperhoneycomb iridate $\beta$-Li$_2$IrO$_3$: First principles calculations

Strongly Correlated Electrons 2021-06-23 v1

Abstract

We studied the electronic structure of β\beta-Li2_2IrO3_3 insulator within the density-functional theory using the generalized gradient approximation with taking into account strong Coulomb correlations in the framework of the fully relativistic spin-polarized Dirac linear muffin-tin orbital band-structure method. The β\beta-Li2_2IrO3_3 undergoes a pressure-induced structural and magnetic phase transitions at PcP_c \sim4 GPa with symmetry lowering to the monoclinic C2/cC2/c. The structural phase transition is accompanied by the formation of Ir2_2 dimers on the zigzag chains, with an Ir-Ir distance of \sim2.66~\AA, even shorter than that of metallic Ir. The strong dimerization stabilizes the bonding molecular-orbital state, leads to the collapse of the magnetism and opens the energy gap with a concomitant electronic phase transition from a Mott insulator to band insulator. The resonant inelastic x-ray scattering spectra (RIXS) at the Ir L3L_3 edge were investigated theoretically from first principles. The calculated results are in good agreement with the experimental data. We show that the the drastic reconstruction of the RIXS spectral peak at 0.7 eV associated with the structural FdddC2/cFddd \rightarrow C2/c phase transition at PcP_c can be related to disappearing of the Coulomb correlations in the high-pressure C2/cC2/c phase

Keywords

Cite

@article{arxiv.2101.06017,
  title  = {Resonant inelastic x-ray scattering spectra in the hyperhoneycomb iridate $\beta$-Li$_2$IrO$_3$: First principles calculations},
  author = {V. N. Antonov and D. A. Kukusta and L. Uba and A. Bonda and S. Uba},
  journal= {arXiv preprint arXiv:2101.06017},
  year   = {2021}
}