Probing electron-phonon interactions away from the Fermi level with resonant inelastic x-ray scattering

DOI: 10.1103/PhysRevX.11.041052

Authors: C. D. Dashwood (University of Cambridge) , A. Geondzhian (Max Planck POSTECH/KOREA Research Initiative; Max Planck Institute for the Structure and Dynamics of Matter) , J. G. Vale (University College London) , A. C. Pakpour-Tabrizi (University College London) , C. A. Howard (University College London) , Q. Faure (University College London) , L. S. I. Veiga (University College London) , D. Meyers (Brookhaven National Laboratory; Oklahoma State University) , G. S. Chiuzbaian (Synchrotron SOLEIL; Sorbonne Université, CNRS) , A. Nicolaou (Synchrotron SOLEIL) , N. Jaouen (Synchrotron SOLEIL) , R. B. Jackman (University College London) , A. Nag (Diamond Light Source) , M. Garcia-Fernandez (Diamond Light Source) , Ke-Jin Zhou (Diamond Light Source) , A. C. Walters (Diamond Light Source) , K. Gilmore (Brookhaven National Laboratory; Humboldt-Universität zu Berlin; European Theoretical Spectroscopy Facility (ETSF)) , D. F. Mcmorrow (University College London) , M. P. M. Dean (Brookhaven National Laboratory)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review X , VOL 11

State: Published (Approved)
Published: December 2021
Diamond Proposal Number(s): 22695

Abstract: Interactions between electrons and lattice vibrations are responsible for a wide range of material properties and applications. Recently, there has been considerable interest in the development of resonant inelastic x-ray scattering (RIXS) as a tool for measuring electron-phonon ( e -ph) interactions. Here, we demonstrate the ability of RIXS to probe the interaction between phonons and specific electronic states both near to, and away from, the Fermi level. We perform carbon K -edge RIXS measurements on graphite, tuning the incident x-ray energy to separately probe the interactions of the π ∗ and σ ∗ electronic states. Our high-resolution data reveal detailed structure in the multiphonon RIXS features that directly encodes the momentum dependence of the e -ph interaction strength. We develop a Green’s-function method to model this structure, which naturally accounts for the phonon and interaction-strength dispersions, as well as the mixing of phonon momenta in the intermediate state. This model shows that the differences between the spectra can be fully explained by contrasting trends of the e -ph interaction through the Brillouin zone, being concentrated at the Γ and K points for the π ∗ states while being significant at all momenta for the σ ∗ states. Our results advance the interpretation of phonon excitations in RIXS and extend its applicability as a probe of e -ph interactions to a new range of out-of-equilibrium situations.

Journal Keywords: Electronic structure; Phonons; Graphite; Resonant inelastic x-ray scattering

Subject Areas: Physics, Materials, Technique Development


Instruments: I21-Resonant Inelastic X-ray Scattering (RIXS)

Other Facilities: SEXTANTS at SOLEIL

Added On: 17/12/2021 08:21

Documents:
PhysRevX.11.041052.pdf

Discipline Tags:

Quantum Materials Physics Hard condensed matter - structures Technique Development - Physics Materials Science

Technical Tags:

Scattering Resonant Inelastic X-ray Scattering (RIXS)