Fermi surface and kink structures in [Formula: see text] revealed by synchrotron-based ARPES

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• The electronic properties of itinerant metamagnets are crucial for understanding emergent quantum phenomena.
• Ruthenates, particularly those with Ruddlesden Popper structures, exhibit complex electronic behaviors.
• Sr$_{6}$Ru$_{3}$O$_{12}$ is an itinerant metamagnet whose electronic structure remains largely unexplored.

Purpose of the Study:

• To elucidate the low-energy electronic structure and Fermi surface topology of Sr$_{6}$Ru$_{3}$O$_{12}$ for the first time.
• To identify and characterize band dispersions, Fermi surface sheets, and their properties.
• To investigate the origin of observed electronic structure features, such as kink structures.

Main Methods:

• Synchrotron-based angle-resolved photoemission spectroscopy (ARPES) was employed to probe the electronic band structure.
• Analysis of quasiparticle band dispersions, considering matrix element effects.
• Determination of Fermi surface topography, effective mass, and carrier character (electron/hole).

Main Results:

• Well-defined quasiparticle band dispersions were resolved, showing dependencies on photon energy and polarization.
• Four bands crossing the Fermi level were identified, leading to four distinct Fermi surface sheets.
• Kink structures with energies between 30-69 meV were observed in the near-Fermi-level band dispersion.

Conclusions:

• The observed kink structures in Sr$_{6}$Ru$_{3}$O$_{12}$ are attributed to strong electron-phonon coupling.
• These findings, combined with prior studies on related ruthenates, suggest a potential universality of strong electron-oxygen phonon coupling in this class of materials.
• The detailed electronic structure mapping provides a foundation for further theoretical and experimental investigations of Sr$_{6}$Ru$_{3}$O$_{12}$ and related compounds.