Facile mechanism to induce topological transition in MXene

Akkus U. O., Balci E., Berber S.

APPLIED SURFACE SCIENCE, cilt.473, ss.597-602, 2019 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 473
  • Basım Tarihi: 2019
  • Doi Numarası: 10.1016/j.apsusc.2018.12.203
  • Dergi Adı: APPLIED SURFACE SCIENCE
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED)
  • Sayfa Sayıları: ss.597-602
  • Anahtar Kelimeler: 2D materials, MXene, Heterostructure, Surfaces and interfaces, Topological electronic structure, Density functional theory, SINGLE DIRAC CONE, CRYSTALS, LAYERS, STATE, AIN, INN
  • Gazi Üniversitesi Adresli: Evet

Özet

We have investigated the electronic structure of the Sc2C(OH)(2) MXene interfacing with a polar AlN multi-layer or a hydrogenated AlN surface. Density functional theory calculations reveal that the nearly free electron (NFE) states of the MXene shift down when the MXene is in contact with a polar flat surface. The Sc2C(OH)(2)/AlN heterostructure shows a Dirac cone and inversion in the band structure. The H-s, Sc-d, and C-p orbitals are involved in the band-inversion. The electronic structure of Sc2C(OH)(2)/AlN heterostructure is found to be topological since the topological invariant Z(2) = 1. We suggest that a band inversion can be induced by contacting with any flat insulating polar surface that has no excess surface-charge. However, it is crucial that the MXene surface is not perturbed (e.g., by dangling bonds). As a proof of concept, we have investigated the electronic structure of Sc2C(OH)(2) adsorbed on a hydrogenated AlN surface and observed band inversion. The band dispersions of the adsorbed MXene are reminiscent of a Weyl semi-metal. The adsorption on a polar material is a facile method to induce a topological electronic structure in the Sc2C(OH)(2) MXene, which may be utilized in various device applications.