Report

Supertwisted spirals of layered materials enabled by growth on non-Euclidean surfaces

See allHide authors and affiliations

Science  23 Oct 2020:
Vol. 370, Issue 6515, pp. 442-445
DOI: 10.1126/science.abc4284

You are currently viewing the abstract.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution

Using curves to make twists

The growth of layered materials on flat substrates usually occurs in stacked layers, although defects or a lattice mismatch can induce strains that distort the shape of subsequent layers. However, these effects are usually small and can be uncontrolled. Zhao et al. now demonstrate the possibility of synthesizing multilayers of two-dimensional materials with certain twists between the layers induced by the presence of screw dislocations in combination with curved substrate surfaces. Different twist angles are achieved by varying the amount of nonplanarity and the character (conical or hyperbolic) of the surface.

Science, this issue p. 442

Abstract

Euclidean geometry is the fundamental mathematical framework of classical crystallography. Traditionally, layered materials are grown on flat substrates; growing Euclidean crystals on non-Euclidean surfaces has rarely been studied. We present a general model describing the growth of layered materials with screw-dislocation spirals on non-Euclidean surfaces and show that it leads to continuously twisted multilayer superstructures. This model is experimentally demonstrated by growing supertwisted spirals of tungsten disulfide (WS2) and tungsten diselenide (WSe2) draped over nanoparticles near the centers of spirals. Microscopic structural analysis shows that the crystal lattice twist is consistent with the geometric twist of the layers, leading to moiré superlattices between the atomic layers.

View Full Text

Stay Connected to Science