Observation of van Hove Singularities in Twisted Silicene Multilayers

TL;DR

This study demonstrates that twisting multilayer silicene at large angles induces van Hove singularities and Moire patterns, revealing a new way to tune its electronic properties for potential electronic applications.

Contribution

It reveals that large-angle interlayer rotation in multilayer silicene creates van Hove singularities, expanding the tunability of its electronic structure.

Findings

Van Hove singularities observed in twisted multilayer silicene.

Large-angle rotation (>20°) induces Moire patterns.

Strong interlayer coupling affects electronic structure.

Abstract

Interlayer interactions perturb the electronic structure of two-dimensional materials and lead to new physical phenomena, such as van Hove singularities and Hofstadter's butterfly pattern. Silicene, the recently discovered two-dimensional form of silicon, is quite unique, in that silicon atoms adopt competing <i>sp</i>² and <i>sp</i>³ hybridization states leading to a low-buckled structure promising relatively strong interlayer interaction. In multilayer silicene, the stacking order provides an important yet rarely explored degree of freedom for tuning its electronic structures through manipulating interlayer coupling. Here, we report the emergence of van Hove singularities in the multilayer silicene created by an interlayer rotation. We demonstrate that even a large-angle rotation (> 20^o) between stacked silicene layers can generate a Moire pattern and van Hove singularities due to the strong interlayer coupling in multilayer silicene. Our study suggests an intriguing method for expanding the tunability of the electronic structure for electronic applications in this two-dimensional material.