Controlling of the Dirac band states of Pb-deposited graphene by using work function difference

Y Tsujikawa,M Sakamoto,Y Yokoi,M Imamura,A Takayama,K Takahashi,R Hobara,T Uchihashi

doi:10.1063/5.0013797

Abstract

We have performed scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES) in Pb-deposited bilayer graphene (BLG) on the SiC(0001) substrate to investigate the dependence of the electronic structures on the Pb-deposition amount. We have observed that the Pb atoms form islands by STM and the π bands of the BLG shift toward the Fermi level by ARPES. This hole-doping-like energy shift is enhanced as the amount of Pb is increased, and we were able to tune the Dirac gap to the Fermi level by 4 ML deposition. Considering the band dispersion, we suggest that the hole-doping-like effect is related to the difference between the work functions of Pb islands and BLG/SiC; the work function of BLG/SiC is lower than that of Pb. Our results propose an easy way of band tuning for graphene with an appropriate selection of both the substrate and deposited material.

Highlights

Yurtsever et al.[12] reported a result of Pb-intercalated monolayer graphene on SiC(0001) with annealing, and they suggest that a holedoping-like effect is caused by decoupling of the buffer layer from the substrate by Pb-termination
We have performed scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES) in Pb-deposited bilayer graphene (BLG) on the SiC(0001) substrate to investigate the dependence of the electronic structures on the Pb-deposition amount
Considering the band dispersion, we suggest that the hole-doping-like effect is related to the difference between the work functions of Pb islands and BLG/SiC; the work function of BLG/SiC is lower than that of Pb

Summary

Introduction

Yurtsever et al.[12] reported a result of Pb-intercalated monolayer graphene on SiC(0001) with annealing, and they suggest that a holedoping-like effect is caused by decoupling of the buffer layer from the substrate by Pb-termination. We have performed scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES) in Pb-deposited bilayer graphene (BLG) on the SiC(0001) substrate to investigate the dependence of the electronic structures on the Pb-deposition amount.

Results

Conclusion