Two-dimensional crystals of semi-metallic van der Waals materials hold much potential for the realization of novel phases, as exemplified by the recent discoveries of a polar metal in few-layer 1T′-WTe 2 and of a quantum spin Hall state in monolayers of the same material. Understanding these phases is particularly challenging because little is known from experiments about the momentum space electronic structure of ultrathin crystals. Here, we report direct electronic structure measurements of exfoliated mono-, bi-, and few-layer 1T′-WTe 2 by laser-based microfocus angle-resolved photoemission. This is achieved by encapsulating with monolayer graphene a flake of WTe 2 comprising regions of different thickness. Our data support the recent identification of a quantum spin Hall state in monolayer 1T′-WTe 2 and reveal strong signatures of the broken inversion symmetry in the bilayer. We finally discuss the sensitivity of encapsulated samples to contaminants following exposure to ambient atmosphere.

Microfocus Laser-Angle-Resolved Photoemission on Encapsulated Mono-, Bi-, and Few-Layer 1T′-WTe 2 / Cucchi, I.; Gutierrez-Lezama, I.; Cappelli, E.; Walker, S. M.; Bruno, F. Y.; Tenasini, G.; Wang, L.; Ubrig, N.; Barreteau, C.; Giannini, E.; Gibertini, M.; Tamai, A.; Morpurgo, A. F.; Baumberger, F.. - In: NANO LETTERS. - ISSN 1530-6984. - 19:1(2019), pp. 554-560. [10.1021/acs.nanolett.8b04534]

Microfocus Laser-Angle-Resolved Photoemission on Encapsulated Mono-, Bi-, and Few-Layer 1T′-WTe 2

Gibertini M.;
2019

Abstract

Two-dimensional crystals of semi-metallic van der Waals materials hold much potential for the realization of novel phases, as exemplified by the recent discoveries of a polar metal in few-layer 1T′-WTe 2 and of a quantum spin Hall state in monolayers of the same material. Understanding these phases is particularly challenging because little is known from experiments about the momentum space electronic structure of ultrathin crystals. Here, we report direct electronic structure measurements of exfoliated mono-, bi-, and few-layer 1T′-WTe 2 by laser-based microfocus angle-resolved photoemission. This is achieved by encapsulating with monolayer graphene a flake of WTe 2 comprising regions of different thickness. Our data support the recent identification of a quantum spin Hall state in monolayer 1T′-WTe 2 and reveal strong signatures of the broken inversion symmetry in the bilayer. We finally discuss the sensitivity of encapsulated samples to contaminants following exposure to ambient atmosphere.
2019
19
1
554
560
Microfocus Laser-Angle-Resolved Photoemission on Encapsulated Mono-, Bi-, and Few-Layer 1T′-WTe 2 / Cucchi, I.; Gutierrez-Lezama, I.; Cappelli, E.; Walker, S. M.; Bruno, F. Y.; Tenasini, G.; Wang, L.; Ubrig, N.; Barreteau, C.; Giannini, E.; Gibertini, M.; Tamai, A.; Morpurgo, A. F.; Baumberger, F.. - In: NANO LETTERS. - ISSN 1530-6984. - 19:1(2019), pp. 554-560. [10.1021/acs.nanolett.8b04534]
Cucchi, I.; Gutierrez-Lezama, I.; Cappelli, E.; Walker, S. M.; Bruno, F. Y.; Tenasini, G.; Wang, L.; Ubrig, N.; Barreteau, C.; Giannini, E.; Gibertini, M.; Tamai, A.; Morpurgo, A. F.; Baumberger, F.
File in questo prodotto:
File Dimensione Formato  
acs.nanolett.8b04534.pdf

Accesso riservato

Tipologia: Versione pubblicata dall'editore
Dimensione 3.51 MB
Formato Adobe PDF
3.51 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

Licenza Creative Commons
I metadati presenti in IRIS UNIMORE sono rilasciati con licenza Creative Commons CC0 1.0 Universal, mentre i file delle pubblicazioni sono rilasciati con licenza Attribuzione 4.0 Internazionale (CC BY 4.0), salvo diversa indicazione.
In caso di violazione di copyright, contattare Supporto Iris

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1200876
Citazioni
  • ???jsp.display-item.citation.pmc??? 4
  • Scopus 51
  • ???jsp.display-item.citation.isi??? 50
social impact