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Nano Research

Article Title

Quasiparticle interference and impurity resonances on WTe2

Authors

Hyeokshin Kwon, Samsung Advanced Institute of Technology, Samsung Electronics Co., Suwon 16678, Republic of Korea
Taehwan Jeong, SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea
Samudrala Appalakondaiah, SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea Department of Nano Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
Youngtek Oh, Samsung Advanced Institute of Technology, Samsung Electronics Co., Suwon 16678, Republic of Korea
Insu Jeon, Samsung Advanced Institute of Technology, Samsung Electronics Co., Suwon 16678, Republic of Korea
Hongki Min, Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea
Seongjun Park, Samsung Advanced Institute of Technology, Samsung Electronics Co., Suwon 16678, Republic of Korea
Young Jae Song, SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea Department of Nano Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 16419, Republic of Korea
Euyheon Hwang, SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea Department of Nano Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
Sungwoo Hwang, Samsung Advanced Institute of Technology, Samsung Electronics Co., Suwon 16678, Republic of Korea

Keywords

WTe2, Weyl semimetal, quasi-particle interference, scanning tunneling microscopy/spectroscopy

Abstract

Using scanning tunneling microscopy/spectroscopy (STM/STS), we examine quasiparticle scattering and interference properties at the surface of WTe2. WTe2, layered transition metal dichalcogenide, is predicted to be a type-II Weyl semimetal. The Weyl fermion states in WTe2 emerge as topologically protected touching points of electron and hole pockets, and Fermi arcs connecting them can be visible in the spectral function on the surface. To probe the properties of surface states, we have conducted low-temperature STM/STS (at 2.7 K) on the surfaces of WTe2 single crystals. We visualize the surface states of WTe2 with atomic scale resolution. Clear surface states emerging from the bulk electron pocket have been identified and their connection with the bulk electronic states shows good agreement with calculations. We show the interesting double resonance peaks in the local density of states appearing at localized impurities. The low-energy resonant peak occurs near the Weyl point above the Fermi energy and it may be mixed with the surface state of Weyl points, which makes it difficult to observe the topological nature of the Weyl semimetal WTe2.

Graphical Abstract

Publisher

Tsinghua University Press

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