title: Direct evidence of interaction-induced Dirac cones in a monolayer silicene/Ag(111) system.
abstract: Silicene, analogous to graphene, is a one-atom-thick 2D crystal of silicon, which is expected to share many of the remarkable properties of graphene. The buckled honeycomb structure of silicene, along with enhanced spin-orbit coupling, endows silicene with considerable advantages over graphene in that the spin-split states in silicene are tunable with external fields. Although the low-energy Dirac cone states lie at the heart of all novel quantum phenomena in a pristine sheet of silicene, a hotly debated question is whether these key states can survive when silicene is grown or supported on a substrate. Here we report our direct observation of Dirac cones in monolayer silicene grown on a Ag(111) substrate. By performing angle-resolved photoemission measurements on silicene(3 × 3)/Ag(111), we reveal the presence of six pairs of Dirac cones located on the edges of the first Brillouin zone of Ag(111), which is in sharp contrast to the expected six Dirac cones centered at the K points of the primary silicene(1 × 1) Brillouin zone. Our analysis shows clearly that the unusual Dirac cone structure we have observed is not tied to pristine silicene alone but originates from the combined effects of silicene(3 × 3) and the Ag(111) substrate. Our study thus identifies the case of a unique type of Dirac cone generated through the interaction of two different constituents. The observation of Dirac cones in silicene/Ag(111) opens a unique materials platform for investigating unusual quantum phenomena and for applications based on 2D silicon systems.
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Defa
authors.initials: D
authors.lastname: Liu
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Baojie
authors.initials: B
authors.lastname: Feng
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Liu
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Zhuojin
authors.initials: Z
authors.lastname: Xie
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Aiji
authors.initials: A
authors.lastname: Liang
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Hu
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Shaolong
authors.initials: S
authors.lastname: He
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Guodong
authors.initials: G
authors.lastname: Liu
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Chuangtian
authors.initials: C
authors.lastname: Chen
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Zuyan
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Chen
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
authors.forename: Kehui
authors.initials: K
authors.lastname: Wu
authors.affiliation: Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546.|Department of Physics, National University of Singapore, Singapore 117542.
authors.forename: Yu-Tzu
authors.initials: YT
authors.lastname: Liu
authors.affiliation: Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546.|Department of Physics, National University of Singapore, Singapore 117542.
authors.forename: Hsin
authors.initials: H
authors.lastname: Lin
authors.affiliation: Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
authors.forename: Zhi-Quan
authors.initials: ZQ
authors.lastname: Huang
authors.affiliation: Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
authors.forename: Chia-Hsiu
authors.initials: CH
authors.lastname: Hsu
authors.affiliation: Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
authors.forename: Feng-Chuan
authors.initials: FC
authors.lastname: Chuang
authors.affiliation: Department of Physics, Northeastern University, Boston, MA 02115.
authors.forename: Arun
authors.initials: A
authors.lastname: Bansil
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; XJZhou@aphy.iphy.ac.cn.|Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.|School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: X J
authors.initials: XJ
authors.lastname: Zhou
keywords: Dirac cone; interaction; photoemission; silicene