Nano-scale displacement sensing based on Van der Waals interaction

TL;DR

This paper introduces a high-resolution nano-scale displacement sensor based on Van der Waals interactions in bi-layer 2D materials, utilizing electronic structure changes detectable by spectroscopy.

Contribution

It demonstrates the use of bi-layer 2D materials' electronic structure variations as a basis for a novel nano-displacement sensor, revealing a universal dz-2 law across different materials.

Findings

Electronic structure varies with lateral and vertical displacement.

The change in band gap is proportional to dz-2, independent of stacking configuration.

The sensor can detect nano-scale displacements via absorption spectroscopy.

Abstract

We propose the nano-scale displacement sensor with high resolution for weak-force systems could be realized based on vertical stacked two-dimensional (2D) atomic corrugated layer materials bound through Van der Waals (VdW) interaction. Using first-principles calculations, we found the electronic structure of bi-layer blue phosphorus (BLBP) varies appreciably to both the lateral and vertical interlayer displacement. The variation of electronic structure due to the lateral displacement is attributed to the changing of the interlayer distance dz led by atomic layer corrugation, which is in a uniform picture with vertical displacement. Despite different stacking configurations, the change of in-direct band gap is proportional to dz-2. This stacking configuration independent dz-2 law is found also works for other graphene-like corrugated bi-layer materials, for example MoS2. By measuring the tunable electronic structure using absorption spectroscopy, the nano-scale displacement could be detected. BLBP represents a large family of bi-layer 2D atomic corrugated materials for which the electronic structure is sensitive to the interlayer vertical and lateral displacement, thus could be used for nano-scale displacement sensor. Since this kind of sensor is established on atomic layers coupled through VdW interaction, it provides unique applications in measurements of nano-scale displacement induced by tiny external force.