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-l...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-ll 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.展开更多
基金We thank K.Lee and J.Heo for useful discussions and other colleagues at the Samsung Advanced Institute of Technology(SAIT)This work has been supported by the Global Research Laboratory Program(No.2016K1A1A2912707)+5 种基金Quantum Computing Development Program(No.2019M3E4A 1080227)the Basic Science Research Program(No.2015M3A7B4050455)the SRC Center for Topological Matter(No.2018R1A5A6075964)through the National Research Foundation(NRF)funded by the Ministry of Science and ICT(MSIT)in KoreaThis work has been supported by Indutrial Strategic Technology Development Program(No.10085617)funded by the Ministry of Trade Industry&Energy(MOTIE)in KoreaThis work has been supported by Institute for Basic Science(No.IBS-R011-D1)Supercomputing resources including technical service were supported by National Institute of Supercomputing and Network through Korea Institute of Science and Technology Information(No.KSC 2018-51-0008).
文摘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-ll 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.
