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. Ourmore » 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.« less

Authors:

Feng, Ya ^[1]; Liu, Defa ^[1]; Feng, Baojie ^[1]; Liu, Xu ^[1]; Zhao, Lin ^[1]; Xie, Zhuojin ^[1]; Liu, Yan ^[1]; Liang, Aiji ^[1]; Hu, Cheng ^[1]; Hu, Yong ^[1]; He, Shaolong ^[1]; Liu, Guodong ^[1]; Zhang, Jun ^[1]; Chen, Chuangtian ^[2]; Xu, Zuyan ^[2]; Chen, Lan ^[1]; Wu, Kehui ^[3]; Liu, Yu-Tzu ^[4]; Lin, Hsin ^[4]; Huang, Zhi-Quan ^[5] more »; Hsu, Chia-Hsiu ^[5]; Chuang, Feng-Chuan ^[5]; Bansil, Arun ^[6]; Zhou, X. J. ^[7] « less

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+ Show Author Affiliations

1. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics, Inst. of Physics
2. Chinese Academy of Sciences (CAS), Beijing (China). Technical Inst. of Physics and Chemistry
3. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics, Inst. of Physics; Collaborative Innovation Center of Quantum Matter, Beijing (China)
4. National Univ. of Singapore (Singapore). Centre for Advanced 2D Materials and Graphene Research Centre, and Dept. of Physics
5. National Sun Yat-Sen Univ., Kaohsiung (Taiwan). Dept. of Physics
6. Northeastern Univ., Boston, MA (United States). Dept. of Physics
7. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics, Inst. of Physics; Collaborative Innovation Center of Quantum Matter, Beijing (China); Univ. of Chinese Academy of Sciences, Beijing (China). School of Physical Sciences

Publication Date:

Wed Dec 07 00:00:00 EST 2016

Research Org.:

Energy Frontier Research Centers (EFRC), Philadelphia, PA (United States). Center for the Computational Design of Functional Layered Materials (CCDM)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1388060

Grant/Contract Number:  

SC0012575

Resource Type:

Journal Article: Accepted Manuscript

Journal Name:

Proceedings of the National Academy of Sciences of the United States of America

Additional Journal Information:

Journal Volume: 113; Journal Issue: 51; Related Information: CCDM partners with Temple University (lead); Brookhaven National Laboratory; Drexel University; Duke University; North Carolina State University; Northeastern University; Princeton University; Rice University; University of Pennsylvania; Journal ID: ISSN 0027-8424

Publisher:

National Academy of Sciences, Washington, DC (United States)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysis (heterogeneous); solar (photovoltaic); energy storage (including batteries and capacitors); hydrogen and fuel cells; defects; mechanical behavior; materials and chemistry by design; synthesis (novel materials); photoemission; silicene; Dirac cone; interaction