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Electron-phonon coupling in the ordered phase of Rb on monolayer graphene

DOI: 10.1016/j.cap.2020.01.010 DOI Help

Authors: Woo Jong Shin (Yonsei University; Pohang University of Science and Technology) , Sung Won Jung (Yonsei University; Diamond Light Source) , Yeongsup Sohn (Yonsei University; Pohang University of Science and Technology) , Sae Hee Ryu (Pohang University of Science and Technology) , Minjae Huh (Yonsei University; Pohang University of Science and Technology, Pohang) , Keun Su Kim (Pohang University of Science and Technology)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Current Applied Physics

State: Published (Approved)
Published: January 2020

Abstract: In the mechanism of two-dimensional (2D) superconductivity in doped graphene, it was predicted that the presence of dopant bands plays a key role. However, it has been challenging to fabricate an ordered phase of alkali metals on graphene owing to its van-der-Waals nature. We systematically study the phase formation of Rb on graphene epitaxially grown on H-passivated SiC(0001). We found a range of control parameters that stabilize the well-ordered 2 × 2 phase (RbC8), as confirmed by in-situ low-energy electron diffraction. Angle-resolved photoemission (ARPES) spectra taken from the 2 × 2 phase show a folded band of graphene and a parabolic band of Rb. In the vicinity of the Fermi level, the self-energy extracted from ARPES data reveals a clear signature of electronic coupling to the in-plane and out-of-plane phonon modes of C and Rb atoms. The electronic coupling of graphene to the in-plane vibration mode of Rb atoms is identified as a key factor for the enhancement of electron-phonon coupling.

Journal Keywords: Graphene; Phase formation; ARPES; Electron-phonon coupling

Subject Areas: Physics, Materials

Facility: Advanced Light Source

Added On: 22/01/2020 09:47

Discipline Tags:

Materials Science Quantum Materials Superconductors Physics Hard condensed matter - electronic properties

Technical Tags: