Nanometric Moire Stripes on the Surface of Bi2Se3 Topological Insulator
Artikel i vetenskaplig tidskrift, 2022

Mismatch between adjacent atomic layers in low-dimensional materials, generating moire 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 moire stripes on the surface of Bi2Se3 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 moire 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 moire superstructure can be instrumental in promoting strong correlations in the topological surface states, which can be responsible for surface magnetism and topological superconductivity.

local density of states

van der Waals epitaxy

topological insulators

moire ? stripes

Bi2Se3

Författare

Matteo Salvato

Universita degli Studi di Roma Tor Vergata

Maurizio De Crescenzi

Universita degli Studi di Roma Tor Vergata

Mattia Scagliotti

Universita degli Studi di Roma Tor Vergata

Paola Castrucci

Universita degli Studi di Roma Tor Vergata

Simona Boninel

Istituto per la Microelettronica e Microsistemi

Giuseppe Mario Caruso

Istituto per la Microelettronica e Microsistemi

Yi Liu

Lunds universitet

Anders Mikkelsen

Lunds universitet

Rainer Timm

Lunds universitet

Suhas Nahas

Uppsala universitet

Annica Black-Schaffer

Uppsala universitet

Gunta Kunakova

Chalmers, Mikroteknologi och nanovetenskap, Kvantkomponentfysik

Jana Andzane

Latvijas Universitate

Donats Erts

Latvijas Universitate

Thilo Bauch

Chalmers, Mikroteknologi och nanovetenskap, Kvantkomponentfysik

Floriana Lombardi

Chalmers, Mikroteknologi och nanovetenskap, Kvantkomponentfysik

ACS Nano

1936-0851 (ISSN) 1936-086X (eISSN)

Vol. 16 9 13860-13868

Ämneskategorier

Materialkemi

Annan fysik

Den kondenserade materiens fysik

DOI

10.1021/acsnano.2c02515

PubMed

36098662

Mer information

Senast uppdaterat

2023-10-25