journal article·2016-03-22Open access

Engineering Electronic Structure of a Two-Dimensional Topological Insulator Bi(111) Bilayer on Sb Nanofilms by Quantum Confinement Effect

Guang Bian, Zhengfei Wang, Xiao-Xiong Wang, Caizhi Xu, SuYang Xu, Thomas Miller, M. Zahid Hasan, Feng Liu, Tai-Chang Chiang

ACS Nano· Volume 10· Issue 3

Abstract

We report on the fabrication of a two-dimensional topological insulator Bi(111) bilayer on Sb nanofilms via a sequential molecular beam epitaxy growth technique. Our angle-resolved photoemission measurements demonstrate the evolution of the electronic band structure of the heterostructure as a function of the film thickness and reveal the existence of a two-dimensional spinful massless electron gas within the top Bi bilayer. Interestingly, our first-principles calculation extrapolating the observed band structure shows that, by tuning down the thickness of the supporting Sb films into the quantum dimension regime, a pair of isolated topological edge states emerges in a partial energy gap at 0.32 eV above the Fermi level as a consequence of quantum confinement effect. Our results and methodology of fabricating nanoscale heterostructures establish the Bi bilayer/Sb heterostructure as a platform of great potential for both ultra-low-energy-cost electronics and surface-based spintronics.
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Research context

OpenAlex topics: Topological Materials and Phenomena · Graphene research and applications · Quantum and electron transport phenomena

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

Affiliations

Joseph Henry Laboratory, Department of Physics, Princeton University, Princeton, New Jersey 08544, United States

Department of Physics, University of Illinois at Urbana—Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080, United States

Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84122, United States

College of Science, Nanjing University of Science and Technology, Nanjing 210094, China

Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana—Champaign, 104 South Goodwin Avenue, Urbana, Illinois 61801-2902, United States

Collaborative Innovation Center of Quantum Matter, Beijing 100084, China

Funding

Gordon and Betty Moore Foundation · Basic Energy Sciences · Natural Science Foundation of Jiangsu Province · Nanjing University of Science and Technology · National Natural Science Foundation of China · Division of Materials Research

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