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Nano Research

Article Title

Atomically smooth ultrathin films of topological insulator Sb2Te3

Authors

Guang Wang, Key Lab for Atomic, Molecular and Nanoscience, Department of Physics, Tsinghua University, Beijing 100084, China
Xiegang Zhu, Key Lab for Atomic, Molecular and Nanoscience, Department of Physics, Tsinghua University, Beijing 100084, China
Jing Wen, Key Lab for Atomic, Molecular and Nanoscience, Department of Physics, Tsinghua University, Beijing 100084, China
Xi Chen, Key Lab for Atomic, Molecular and Nanoscience, Department of Physics, Tsinghua University, Beijing 100084, China
Ke He, Institute of Physics, the Chinese Academy of Sciences, Beijing 100190, China
Lili Wang, Institute of Physics, the Chinese Academy of Sciences, Beijing 100190, China
Xucun Ma, Institute of Physics, the Chinese Academy of Sciences, Beijing 100190, China
Ying Liu, Department of Physics, The Pennsylvania State University, Pennsylvania 16802, USA Department of Physics, Shanghai Jiaotong University, Shanghai 200240, China Department of Physics, Zhejiang University, Hangzhou, China
Xi Dai, Institute of Physics, the Chinese Academy of Sciences, Beijing 100190, China
Zhong Fang, Institute of Physics, the Chinese Academy of Sciences, Beijing 100190, China
Jinfeng Jia, Key Lab for Atomic, Molecular and Nanoscience, Department of Physics, Tsinghua University, Beijing 100084, China Department of Physics, Shanghai Jiaotong University, Shanghai 200240, China
Qikun Xue, Key Lab for Atomic, Molecular and Nanoscience, Department of Physics, Tsinghua University, Beijing 100084, China Institute of Physics, the Chinese Academy of Sciences, Beijing 100190, China

Keywords

Topological insulator, electronic structure, scanning tunneling microscopy, angle-resolved photoemission spectroscopy, molecular beam epitaxy

Abstract

The growth and characterization of single-crystalline thin films of topological insulators (TIs) is an important step towards their possible applications. Using in situ scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES), we show that moderately thick Sb2Te3 films grown layer-by-layer by molecular beam epitaxy (MBE) on Si(111) are atomically smooth, single-crystalline, and intrinsically insulating. Furthermore, these films were found to exhibit a robust TI electronic structure with their Fermi energy lying within the energy gap of the bulk that intersects only the Dirac cone of the surface states. Depositing Cs in situ moves the Fermi energy of the Sb2Te3 films without changing the electronic band structure, as predicted by theory. We found that the TI behavior is preserved in Sb2Te3 films down to five quintuple layers (QLs).

Graphical Abstract

Publisher

Tsinghua University Press

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