Strain Switching in van der Waals Heterostructures triggered by a Spin-Crossover Metal Organic Framework

TL;DR

This paper explores van der Waals heterostructures combining spin-crossover molecular layers with graphene, demonstrating strain-induced property changes and advancing the field of straintronics with bistable molecular components.

Contribution

It introduces a novel type of vdWH with SCO layers and graphene, showing how spin transitions induce strain and modify material properties, expanding the scope of 2D heterostructures.

Findings

Spin transition induces strain in heterostructures.

Properties of heterostructures are tunable via spin state.

Molecular/inorganic heterostructures enable straintronics applications.

Abstract

Van der Waals heterostructures (vdWHs) combine different layered materials with properties of interest,1 such as two-dimensional (2D) semimetals, semiconductors, magnets or superconductors. These heterostructures provide the possibility of engineering new materials with emergent functionalities that are not accessible in another way. Beyond inorganic 2D materials, layered molecular materials remain still rather unexplored, with only few examples regarding their isolation as atomically thin-layers. By a proper chemical design, the physical properties of these systems can be tuned, as illustrated by the so-called spin-crossover (SCO) compounds, in which a spin transition can be induced by applying external stimuli like light, temperature, pressure or an electric field. Here, we report on vdWHs formed by SCO layers and few-layers graphene, being its properties modified by the strain concomitant to the spin transition. These molecular/inorganic vdWHs represent the deterministic incorporation of bistable molecular layers with other 2D materials of interest in the emergent field of straintronics.