One‐Interlayer‐Twisted Multilayer MoS₂ Moiré Superlattices

Abstract

Twist angle provides a new degree of freedom for 2D material modifications. In principle, the intrinsic properties of twisted multilayers can be regulated by twist angle between each adjacent layer and thus have greater tunability than widely studied bilayer structures. Considering its complexity, it is important to first investigate the simplest twisted multilayers with only one interface twisted. In this work, multilayer Moiré superlattices with only one twisted interface via paraffin‐assisted folding of non‐twisted stacked (highly symmetrically stacked) multilayer MoS2 are successfully fabricated, and their twist‐angle dependent optical properties are systematically studied. Compared to non‐twisted stacked multilayer MoS2, the one‐interface‐twisted multilayers show a 2–3.5 times higher PL intensity, and their interlayer coupling, indirect bandgap, and degree of circular polarization (DOCP) are tunable by twist angle. Notably, the DOCP for the one‐interface‐twisted four‐layer (folded bilayer) can reach 86%, which is the highest value ever reported for transition metal dichalcogenide homostructures above liquid nitrogen temperature. This work provides a solid base for understanding twist‐angle dependent properties of twisted multilayer 2D‐materials.

Breaking Rotational Symmetry in Supertwisted WS2 Spirals via Moiré Magnification of Intrinsic Heterostrain

“…Theoretical studies have revealed fascinating physical properties in continuously twisted multilayer systems, forming the basis for “3D twistronics”; , for example, quantum geometry has been predicted to govern superconductivity and superfluidity in platforms including, but not limited to, twisted multilayer graphene . However, the “tear-and-stack” technique, the most prevalent way to fabricate twisted 2D structures, has limited capability and throughput for creating 3D twistronics. , In light of this limitation, direct synthesis of continuously twisted TMD structures, termed “supertwisted spirals”, has been achieved via screw dislocation driven growth on non-Euclidean surfaces …”

“…10 However, the "tearand-stack" technique, the most prevalent way to fabricate twisted 2D structures, has limited capability and throughput for creating 3D twistronics. 20,21 In light of this limitation, direct synthesis of continuously twisted TMD structures, termed "supertwisted spirals", has been achieved via screw dislocation driven growth on non-Euclidean surfaces. 11 The presence of screw dislocations and curved substrates disrupts the perfect crystalline periodicity, thereby inducing a native strain field in supertwisted spirals.…”

Inversion Symmetry and Exotic Interlayer Exciton Behavior in Twisted Trilayer MoS2 Produced by Vapor Deposition

“…Artificial stacking has been used extensively in constructing twist multilayer systems, but the transfer process is complicated, and it is not suitable for the systematic study of the twist angle-related characteristics of 2DMs . The emerging paraffin-assisted folding strategy on untwisted stacked multilayers of MoS 2 can construct a multilayer interlayer structure with only one twisted lattice interface, but it is time-consuming. , Thus, it is of great importance to obtain twisted multilayer MoS 2 in a stable and easy-to-fabricate method.…”

“…Unfortunately, with enormous amounts of possible combinations of twist angles at different layer interfaces, the investigation of the twisted multilayer is much more complicated than that of the twisted bilayer. Therefore, it is necessary to fabricate multilayer structures that contain one-interlayer-twisted to understand the effects of twisted multilayer systems . Artificial stacking has been used extensively in constructing twist multilayer systems, but the transfer process is complicated, and it is not suitable for the systematic study of the twist angle-related characteristics of 2DMs .…”

“…Therefore, it is necessary to fabricate multilayer structures that contain one-interlayer-twisted to understand the effects of twisted multilayer systems. 10 Artificial stacking has been used extensively in constructing twist multilayer systems, but the transfer process is complicated, and it is not suitable for the systematic study of the twist anglerelated characteristics of 2DMs. 11 The emerging paraffinassisted folding strategy on untwisted stacked multilayers of MoS 2 can construct a multilayer interlayer structure with only one twisted lattice interface, but it is time-consuming.…”