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Nanometric Moiré Stripes on the Surface of Bi2Se3Topological Insulator

Salvato, Matteo ; Crescenzi, Maurizio De ; Scagliotti, Mattia ; Castrucci, Paola ; Boninelli, Simona ; Caruso, Giuseppe Mario ; Liu, Yi LU ; Mikkelsen, Anders LU ; Timm, Rainer LU orcid and Nahas, Suhas , et al. (2022) In ACS Nano 16(9). p.13860-13868
Abstract

Mismatch between adjacent atomic layers in low-dimensional materials, generating moiré patterns, has recently emerged as a suitable method to tune electronic properties by inducing strong electron correlations and generating novel phenomena. Beyond graphene, van der Waals structures such as three-dimensional (3D) topological insulators (TIs) appear as ideal candidates for the study of these phenomena due to the weak coupling between layers. Here we discover and investigate the origin of 1D moiré stripes on the surface of Bi2Se3TI thin films and nanobelts. Scanning tunneling microscopy and high-resolution transmission electron microscopy reveal a unidirectional strained top layer, in the range 14-25%, with respect... (More)

Mismatch between adjacent atomic layers in low-dimensional materials, generating moiré patterns, has recently emerged as a suitable method to tune electronic properties by inducing strong electron correlations and generating novel phenomena. Beyond graphene, van der Waals structures such as three-dimensional (3D) topological insulators (TIs) appear as ideal candidates for the study of these phenomena due to the weak coupling between layers. Here we discover and investigate the origin of 1D moiré stripes on the surface of Bi2Se3TI thin films and nanobelts. Scanning tunneling microscopy and high-resolution transmission electron microscopy reveal a unidirectional strained top layer, in the range 14-25%, with respect to the relaxed bulk structure, which cannot be ascribed to the mismatch with the substrate lattice but rather to strain induced by a specific growth mechanism. The 1D stripes are characterized by a spatial modulation of the local density of states, which is strongly enhanced compared to the bulk system. Density functional theory calculations confirm the experimental findings, showing that the TI surface Dirac cone is preserved in the 1D moiré stripes, as expected from the topology, though with a heavily renormalized Fermi velocity that also changes between the top and valley of the stripes. The strongly enhanced density of surface states in the TI 1D moiré superstructure can be instrumental in promoting strong correlations in the topological surface states, which can be responsible for surface magnetism and topological superconductivity.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
BiSe, local density of states, moiré stripes, topological insulators, van der Waals epitaxy
in
ACS Nano
volume
16
issue
9
pages
9 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85138785501
  • pmid:36098662
ISSN
1936-0851
DOI
10.1021/acsnano.2c02515
language
English
LU publication?
yes
id
bc53e080-ff2f-4ce5-9883-b2508047b56a
date added to LUP
2022-12-12 08:57:47
date last changed
2024-12-14 17:28:45
@article{bc53e080-ff2f-4ce5-9883-b2508047b56a,
  abstract     = {{<p>Mismatch between adjacent atomic layers in low-dimensional materials, generating moiré patterns, has recently emerged as a suitable method to tune electronic properties by inducing strong electron correlations and generating novel phenomena. Beyond graphene, van der Waals structures such as three-dimensional (3D) topological insulators (TIs) appear as ideal candidates for the study of these phenomena due to the weak coupling between layers. Here we discover and investigate the origin of 1D moiré stripes on the surface of Bi<sub>2</sub>Se<sub>3</sub>TI thin films and nanobelts. Scanning tunneling microscopy and high-resolution transmission electron microscopy reveal a unidirectional strained top layer, in the range 14-25%, with respect to the relaxed bulk structure, which cannot be ascribed to the mismatch with the substrate lattice but rather to strain induced by a specific growth mechanism. The 1D stripes are characterized by a spatial modulation of the local density of states, which is strongly enhanced compared to the bulk system. Density functional theory calculations confirm the experimental findings, showing that the TI surface Dirac cone is preserved in the 1D moiré stripes, as expected from the topology, though with a heavily renormalized Fermi velocity that also changes between the top and valley of the stripes. The strongly enhanced density of surface states in the TI 1D moiré superstructure can be instrumental in promoting strong correlations in the topological surface states, which can be responsible for surface magnetism and topological superconductivity.</p>}},
  author       = {{Salvato, Matteo and Crescenzi, Maurizio De and Scagliotti, Mattia and Castrucci, Paola and Boninelli, Simona and Caruso, Giuseppe Mario and Liu, Yi and Mikkelsen, Anders and Timm, Rainer and Nahas, Suhas and Black-Schaffer, Annica and Kunakova, Gunta and Andzane, Jana and Erts, Donats and Bauch, Thilo and Lombardi, Floriana}},
  issn         = {{1936-0851}},
  keywords     = {{BiSe; local density of states; moiré stripes; topological insulators; van der Waals epitaxy}},
  language     = {{eng}},
  month        = {{09}},
  number       = {{9}},
  pages        = {{13860--13868}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{ACS Nano}},
  title        = {{Nanometric Moiré Stripes on the Surface of Bi<sub>2</sub>Se<sub>3</sub>Topological Insulator}},
  url          = {{http://dx.doi.org/10.1021/acsnano.2c02515}},
  doi          = {{10.1021/acsnano.2c02515}},
  volume       = {{16}},
  year         = {{2022}},
}