Chiral twisted van der Waals nanowires
- Univ. of Nebraska-Lincoln, Lincoln, NE (United States). Dept. of Electrical and Computer Engineering
- Univ. of Nebraska-Lincoln, Lincoln, NE (United States). Dept. of Mechanical and Materials Engineering
Van der Waals heterostructures with small misalignment between adjacent layers (‘interlayer twist’) are of interest because of electronic structure and correlation phenomena (such as superconductivity) that are determined by both the atomic lattice and long-range superlattice potentials arising in interlayer moiré patterns. Previously, such twisted heterostructures have involved a single planar interface between layers isolated by exfoliation and micromechanically stacked in the desired relative orientation. Here we demonstrate a class of materials—van der Waals nanowires of layered crystals—in which a tunable interlayer twist evolves naturally during synthesis. In vapour–liquid–solid growth, nanowires of germanium(ii) sulfide, an anisotropic layered semiconductor, crystallize with layering along the wire axis and have a strong propensity for forming axial screw dislocations. Nanometre-resolved electron diffraction shows that Eshelby twist, induced by a torque on the ends of a cylindrical solid due to the stress field of an axial dislocation, causes a chiral structure in the van der Waals nanowires. The in-plane germanium sulfide crystal axes progressively rotate along the wire, and germanium sulfide layers in adjacent turns of the helix naturally form a moiré pattern because of their interlayer twist. The axial rotation and the twist are tunable by varying the nanowire thickness. Combined electron diffraction and cathodoluminescence spectroscopy show the correlation between the interlayer twist and locally excited light emission that is due to progressive changes in the lattice orientation and in the interlayer moiré registry along the nanowires. Furthermore, the findings demonstrate a step towards scalable fabrication of van der Waals structures with defined twist angles, in which interlayer moiré patterns are realized along a helical path on a nanowire instead of a planar interface.
- Research Organization:
- Univ. of Nebraska, Lincoln, NE (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
- Grant/Contract Number:
- SC0016343
- OSTI ID:
- 1573810
- Journal Information:
- Nature (London), Vol. 570, Issue 7761; ISSN 0028-0836
- Publisher:
- Nature Publishing GroupCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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