Monolayer charge-neutral graphene on platinum with extremely weak electron-phonon coupling

Abstract

Epitaxial growth of graphene on transition metal substrates is an important route for obtaining large scale graphene. However, the interaction between graphene and the substrate often leads to multiple orientations, distorted graphene band structure, large doping and strong electron-phonon coupling. Here we report the growth of monolayer graphene with high crystalline quality on Pt(111) substrate by using very low concentration of internal carbon source with high annealing temperature. The controlled growth leads to electronically decoupled graphene: it is nearly charge neutral and has extremely weak electron-phonon coupling (coupling strength λ ≈ 0.056) as revealed by angle-resolved photoemission spectroscopic measurements. The thermodynamics and kinetics of carbon diffusion process is investigated by DFT calculation. Such graphene with negligible graphene-substrate interaction provides an important platform for fundamental research as well as device applications when combined with nondestructive sample transfer technique.

Hole doping, hybridization gaps, and electronic correlation in graphene on a platinum substrate

“…These findings are very different from the previous ARPES results on graphene/Pt(111) 12,13 that report freestanding nature of graphene, but consistent with first-principles calculation for the same system 14,15 . Concomitantly, the π band of graphene on Pt differs from that of graphene on other metallic substrates as discussed below 17-20 .…”

“…Although weak hole doping of 0.10 eV and 0.06 eV has been observed from graphene on Ir(111) 30 and Pt(111) 13 substrates, respectively, the graphene π band is comparable to that of nearly freestanding graphene for these cases. On the other hand, another experimental studies on graphene on a Pt(111) substrate show that the graphene π band exhibits a deeper hole-doping of 0.15 eV 10,11 and complex hybridization resulting in nontrivial spin structure of the π band.…”

“…2 and 3 or single crystal Pt(111) 10,11 , crystallinity of Pt does not play a crucial role in the observed strong interaction between graphene and Pt. On the other hand, the latter using carbon surface segregation 12,13 shows the absence of the hybridization and weaker hole-doping. Es-pecially, for the case of higher temperature segregation, e. g. , 1600 • C 13 , the electron band structure of the Pt substrate completely disappears.…”

“…For example, a Raman spectroscopy study on the interface between graphene and Pt reports strongly suppressed Raman signals from graphene signifying strong interactions between them 9 , which can possibly cause Rashba-type spin splitting in graphene 10,11 . On the other hand, a recent experimental study on the electron band structure of graphene on a Pt(111) surface shows that overlying graphene exhibits typical characteristics of free-standing graphene 12,13 . However, first-principles calculations support strong interactions between graphene and Pt 14,15 .…”

Stacking-Dependent Electronic Structure of Trilayer Graphene Resolved by Nanospot Angle-Resolved Photoemission Spectroscopy

“…33 The sample was annealed at 450 • C to clean the surface before the ARPES measurements. NanoARPES experiments were performed at the ANTARES beamline of the SOLEIL synchrotron, France.…”