Twist Angle-Dependent Atomic Reconstruction and Moiré Patterns in Transition Metal Dichalcogenide Heterostructures

Abstract

Van der Waals layered materials, such as transition metal dichalcogenides (TMDs), are an exciting class of materials with weak interlayer bonding which enables one to create so-called van der Waals heterostructures (vdWH). 1 One promising attribute of vdWH is the ability to rotate the layers at arbitrary azimuthal angles relative to one another. Recent work has shown that control of the twist angle between layers can have a dramatic effect on vdWH properties, including the appearance of superconductivity, 2,3 emergent electronic states, 4-7 and unique optoelectronic behavior. 6-11 For TMD vdWH, twist angle has been treated solely through the use of rigid-lattice moiré patterns. No atomic reconstruction, i.e. any rearrangement of atoms within the individual layers, has been reported experimentally to date. However, any atomic level reconstruction can be expected to have a significant impact on the band structure and all measured properties, and

Duality between atomic configurations and Bloch states in twistronic materials

“…The anharmonicity in the effective mass and interlayer coupling will be necessary for accurate comparison to experimental results, but the overall intuition for the moiré flat bands is unchanged. In addition, in-plane relaxations at small twist angles form domain-wall structures [46][47][48][49] and will cause the moiré potential to become independent of the twist angle [50]. This prevents the tuning of ω to arbitrarily small values, and will define a minimum possible bandwidth for the flat bands.…”

Bond states, moiré patterns, and bandgap modulation of two-dimensional BN/SiC van der Waals heterostructures

“…Previous studies have found that the moiré pattern is obtained by rotating the angle of two atomic layers of 2D materials. 18 However, we found that the 2D material with a single layer of the wave shape structure can obtain moiré patterns at different incident angles. Fig.…”

“…17 Rosenberger et al studied the moiré pattern of a transition metal dichalcogenide heterostructure and found that the angle rotation is related. 18 Cao et al found that the superconducting properties of two layers of graphene were exhibited at specific angles (approximately 1.11). 19 Therefore, matching lattice strains of interlayer couplings and angle rotation of the two atomic layer heterojunctions will form a moiré pattern.…”

Near‐Unity Polarization of Valley‐Dependent Second‐Harmonic Generation in Stacked TMDC Layers and Heterostructures at Room Temperature

“…[ 30,33 ] Besides the AA and AB stacking with corresponding orientation angles of 0° and 60°, other specific orientation angles such as 30° can also be formed during the growth but with much lower chance and control, due to the required larger stacking energy. [ 34 ] The bright‐field optical images ( Figure a) show the triangular‐shaped WSe 2 atomic layers with different orientational angles with respect to each other. The number of layers can be preliminarily determined by the optical contrast and further verified by atomic force microscopy (AFM) and Raman spectroscopy measurements (Figures S3 and S4, Supporting Information).…”