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Tendency of Gap Opening in Semimetal 1T′‐MoTe 2 with Proximity to a 3D Topological Insulator
Author(s) -
Zhang Cheng,
Liu Wei,
Zhan Fangyang,
Zhang Teng,
Liu Liwei,
Zhang Min,
Xie Sen,
Li Ziwei,
Sang Hao,
Ge Haoran,
Yan Yonggao,
Wang Rui,
Wang Yeliang,
Zhang Qingjie,
Tang Xinfeng
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202103384
Subject(s) - topological insulator , materials science , semimetal , condensed matter physics , heterojunction , band gap , photoemission spectroscopy , topology (electrical circuits) , van der waals force , monolayer , scanning tunneling spectroscopy , valence (chemistry) , spectroscopy , scanning tunneling microscope , x ray photoelectron spectroscopy , nanotechnology , physics , optoelectronics , quantum mechanics , nuclear magnetic resonance , mathematics , combinatorics , molecule
Monolayer (ML) 1T′‐MoTe 2 has attracted intensive interest as a fascinating quantum spin Hall (QSH) insulator. However, there are two critical aspects impeding its exploration and potential applications of QSH effects. One is its semimetallic feature with a negative band gap, leading to nontrivial edge channels annihilated by the bulk states. The other is its fabrication always accompanied by a mixed phase of 1T′ and 2H. Based on first‐principles calculations, it is shown that the large work‐function difference results in strong interlayer interactions and proximity effects in ML 1T′‐MoTe 2 via interfacing a 3D topological insulator Bi 2 Te 3 , facilitating the realization of pure 1T′ phase and even the band gap opening. It is further verified that the epi‐grown ML 1T′‐MoTe 2 on Bi 2 Te 3 is nearly in single phase. Furthermore, the measurements of angle resolved photoemission spectroscopy and scanning tunneling spectroscopy confirm the obvious separated‐tendency of conduction and valence bands as well as the strong metallic edge states in ML 1T′‐MoTe 2 . The results also reveal the nontrivial band topology in ML 1T′‐MoTe 2 is preserved in 1T′‐MoTe 2 /Bi 2 Te 3 heterostructure. This work offers a promising candidate to realize QSH effects and provides guidance for controlling the nontrivial band gap opening by proximity effects in van der Waals engineering.