Te vacancy-driven superconductivity in orthorhombic molybdenum ditelluride

Suyeon Cho, Se Hwang Kang, Ho Sung Yu, Hyo Won Kim, Wonhee Ko, Sung Woo Hwang, Woo Hyun Han, Duk Hyun Choe, Young Hwa Jung, Kee Joo Chang, Young Hee Lee, Heejun Yang, Sung Wng Kim

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have received great attentions because of diverse quantum electronic states such as topological insulating (TI), Weyl semimetallic (WSM) and superconducting states. Recently, the superconducting states emerged in pressurized semimetallic TMDs such as MoTe2 and WTe2 have become one of the central issues due to their predicted WSM states. However, the difficulty in synthetic control of chalcogen vacancies and the ambiguous magneto transport properties have hindered the rigorous study on superconducting and WSM states. Here, we report the emergence of superconductivity at 2.1 K in Te-deficient orthorhombic Td-MoTe2-x with an intrinsic electron-doping, while stoichiometric monoclinic 1T'-MoTe2 shows no superconducting state down to 10 mK, but exhibits a large magnetoresistance of 32 000% at 2 K in a magnetic field of 14 T originating from nearly perfect compensation of electron and hole carriers. Scanning tunnelling spectroscopy and synchrotron x-ray diffraction combined with theoretical calculations clarify that Te vacancies trigger superconductivity via intrinsic electron doping and the evolution of the Td phase from the 1T' phase below 200 K. Unlike the pressure-induced superconducting state of monoclinic MoTe2, this Te vacancy-induced superconductivity is emerged in orthorhombic MoTe2, which is predicted as Weyl semimetal, via electron-doping. This chalcogen vacancy induced-superconductivity provides a new route for cultivating superconducting state together with WSM state in 2D van der Waals materials.

Original languageEnglish
Article number021030
Journal2D Materials
Volume4
Issue number2
DOIs
StatePublished - Jun 2017

Bibliographical note

Funding Information:
This work was supported by the Institute for Basic Science (IBS-R011-D1), the National Research Foundation of Korea (NRF) under Grant No. 2015M3D1A1070639, and NRF Nano·Material Technology Development Program (NRF) under Grant No. 2012M3A7B4049652 in Korea. SC was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2017R1A2B4010423). WHH, DHC and KJC were supported by Samsung Science and Technology Foundation under Grant No. SSTFBA1401-08.

Publisher Copyright:
© 2017 IOP Publishing Ltd

Keywords

  • Superconductivity
  • Topological semimetal
  • Transition metal dichalcogenides

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