Moiré-pattern-modulated electronic structures in Sb2Te3/graphene heterostructure

Abstract

Moiré superlattice has recently been found in topological insulators, which can lead to periodic modulation on the electronic structure. In this work, we report the low-temperature scanning tunneling microscopy study of Sb 2 Te 3 films grown on graphitized 4H-SiC. We find that substrate temperature can strongly influence the rotation angles between Sb 2 Te 3 film and graphene substrate. Three kinds of moiré patterns are observed at the first quintuple layer Sb 2 Te 3 film under different substrate temperatures. One shows complicated patterns with a rotation angle of nearly 0° relative to the substrate, another just exhibits simple 1 × 1 structure with a rotation angle of 30°. Other rotation angle like 8.2° is observed at higher substrate temperature as well, which is relatively rare. Comparison of the dI/dV curves from Sb 2 Te 3 films with different moiré patterns indicates that the superstructure can offer degrees of freedom in tailoring electronic structure. This work may stimulate the further study on the moiré modulation to the electronic properties of topological insulators.

Nanometric Moiré Stripes on the Surface of Bi2Se3 Topological Insulator

“…Modulated moiré stripes on the surface of TI thin films have been previously reported in the literature and ascribed to several effects, such as chemical doping, inhomogeneity, Friedel oscillations, and substrate mismatch . In our case, doping can be ruled out due to the absence of any precursor during the growth process and the quasi-perfect stoichiometry obtained by our growth method .…”

“…Modulated moiré stripes on the surface of TI thin films have been previously reported in the literature and ascribed to several effects, such as chemical doping, 17 inhomogeneity, 18 Friedel oscillations, 19 and substrate mismatch. 20 In our case, doping can be ruled out due to the absence of any precursor during the growth process and the quasi-perfect stoichiometry obtained by our growth method. 14 Chemical inhomogeneity can also be ruled out because all possible Bi x Se y compounds have a , b , and/or c axis lengths different from those of Bi 2 Se 3 or have a different lattice structure, 21 which would be detectable by a combined X-ray diffraction and HRTEM analysis.…”

Modulating the periods and electronic properties of striped moiré superstructures for monolayer WSe2 on Au(100) by varied interface coupling

“…14 In addition, similar relative-rotation-dependent band structure modulation was also reported in the monolayer Sb 2 Te 3 /graphene heterostructure. 28 The dI/dV spectra for the 0°rotated region presented an energy shift towards the Fermi level with respect to that of the 30°rotated region. The 30°r otated region induced smaller lattice strain and stronger interface charge transfer than that without rotation.…”

“…26 In addition, the local electronic structures of Sb 2 Te 3 films grown on graphitized 4H-SiC, were also reported to be significantly modulated by the moiré pattern. 28 Recently, proximity-effect-induced superconductivity of monolayer MoS 2 on top of a Pb(111) thin film was found to depend on the spatial distribution of the hexagonal moiré pattern. 29…”

“…26 In addition, the local electronic structures of Sb 2 Te 3 films grown on graphitized 4H-SiC, were also reported to be significantly modulated by the moiré pattern. 28 Recently, proximity-effect-induced superconductivity of monolayer MoS 2 on top of a Pb(111) thin film was found to depend on the spatial distribution of the hexagonal moiré pattern. 29 In addition to the commonly observed hexagonal shape moiré patterns in 2D lattices, the lattice symmetry mismatch between 2D materials and substrates can induce the formation of a variety of novel striped moiré superstructures, as reported in monolayer MoS 2 /Au(100) 30 and WS 2 /Au(100).…”