Layered 2D crystals by design: optimisation of Sb$_2$Te$_3$-GeTe van der Waals superlattices

TL;DR

This paper introduces a genetic algorithm to optimize layered 2D heterostructures, specifically applied to Sb$_2$Te$_3$-GeTe superlattices, with experimental validation showing close agreement with computational predictions.

Contribution

It presents a novel optimization method for designing layered 2D heterostructures and demonstrates its effectiveness through experimental synthesis and validation.

Findings

Optimized superlattice structure closely matches experimental XRD spectra.

The structure is within 0.92 meV/atom of the known lowest energy configuration.

The method successfully guides experimental growth of targeted 2D heterostructures.

Abstract

Herein a genetic algorithm for optimising the design of layered 2D heterostructure is proposed. As a proof-of-concept it is applied to Sb$_2$Te$_3$-GeTe phase-change material superlattices, and the resulting lowest energy structure is grown experimentally. The similarity of the computational and experimental structures is verified with the comparison of XRD spectra. The structure is found to be within 0.92 meV/at. from the energetically most favorable known structure for Ge$_2$Sb$_2$Te$_5$.