Direct Observation at Room Temperature of the Orthorhombic Weyl Semimetal Phase in Thin Epitaxial MoTe2

The direct observation at room temperature (RT) of the noncentrosymmetric orthorhombic topological Weyl semimetal phase in epitaxial thin films of MoTe2 grown on InAs(111)/Si(111) substrates by molecular beam epitaxy (MBE) is reported. The orthorhombic phase is typically found at lower temperatures...

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Bibliographic Details
Published in:Advanced functional materials 2018-08, Vol.28 (33), p.n/a
Main Authors: Tsipas, Polychronis, Fragkos, Sotirios, Tsoutsou, Dimitra, Alvarez, Carlos, Sant, Roberto, Renaud, Gilles, Okuno, Hanako, Dimoulas, Athanasios
Format: Article
Language:English
Subjects:
2D materials
Charge transport
Diffraction
Epitaxial growth
Interlayers
Lattice parameters
Materials science
Molecular beam epitaxy
Molecular beams
Molybdenum compounds
orthorhombic MoTe2
Orthorhombic phase
Room temperature
Silicon substrates
Stacking
Tellurides
Thin films
transmission electron microscopy
Weyl semimetal
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Summary:The direct observation at room temperature (RT) of the noncentrosymmetric orthorhombic topological Weyl semimetal phase in epitaxial thin films of MoTe2 grown on InAs(111)/Si(111) substrates by molecular beam epitaxy (MBE) is reported. The orthorhombic phase is typically found at lower temperatures but its observation at RT in this work is attributed to the enlarged lattice parameters, influenced by the substrate, which stabilize an interlayer antibonding state compatible with the orthorhombic stacking. First‐principles calculations predict eight type II Weyl nodes which are located below (but near) the Fermi energy making them accessible to charge transport and creating the prospect for practical applications exploiting the nontrivial topological properties. The orthorhombic phase coexists with an unconventional triclinic layer stacking which is different than the monoclinic or orthorhombic structures but it is centrosymmetric and topologically trivial. The room temperature observation of the noncentrosymmetric orthorhombic phase of epitaxial MoTe2 on InAs(111) substrate is reported. Due to enlarged lattice parameters of 1–3 monolayers films a type II topological Weyl semimetal is predicted with Weyl nodes located a few meV below the Fermi level, accessible to transport.
ISSN:1616-301X
1616-3028
DOI:10.1002/adfm.201802084