High-resolution resonant inelastic x-ray scattering study of the electron-phonon coupling in honeycomb $\alpha$-Li${}_2$IrO${}_3$

Abstract

The excitations in honeycomb $\alpha$-Li${}_2$IrO${}_3$ have been investigated with high-resolution resonant inelastic x-ray scattering (RIXS) at the O K edge. The low-energy response is dominated by a fully resolved ladder of excitations, which we interpret as being due to multi-phonon processes in the presence of strong electron-phonon coupling (EPC). At higher energies, the orbital excitations are shown to be dressed by phonons. The high quality of the data permits a quantitative test of the analytical model for the RIXS cross-section, which has been proposed to describe EPC in transition metal oxides (TMOs). We find that the magnitude of the EPC is comparable to that found for a range of 3d TMOs. This indicates that EPC may be of equal importance in determining the phenomenology displayed by corresponding 5d based systems.

Accepted in Physical Review B

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Cited by in corpus (4)

• Nearly itinerant electronic groundstate in the intercalated honeycomb iridate Ag${}_3$LiIr${}_2$O${}_6$
• Magnetic excitations in double perovskite iridates La${}_2$$M$IrO${}_6$ ($M$ = Co, Ni, and Zn) mediated by 3$d$-5$d$ hybridization
• Optical magnons with dominant bond-directional exchange interactions in a honeycomb lattice iridate $\alpha$-Li${}_2$IrO${}_3$
• Non-local features of the spin-orbit exciton in Kitaev materials