Simultaneous Prediction of the Magnetic and Crystal Structure of Materials Using a Genetic Algorithm

Abstract

We introduce a number of extensions and enhancements to a genetic algorithm for crystal structure prediction, to make it suitable to study magnetic systems. The coupling between magnetic properties and crystal structure means that it is essential to take a holistic approach, and we present for the first time, a genetic algorithm that performs a simultaneous global optimisation of both magnetic structure and crystal structure. We first illustrate the power of this approach on a novel test system—the magnetic Lennard−Jones potential—which we define. Then we study the complex interface structures found at the junction of a Heusler alloy and a semiconductor substrate as found in a proposed spintronic device and show the impact of the magnetic interface structure on the device performance.

Keywords

• structure prediction
• magnetic materials
• genetic algorithm
• global optimisation
• ab initio
• DFT
• structural fingerprint
• magnetic Lennard–Jones
• Heusler alloy
• half-Heusler alloy