Degree Type

Thesis

Date of Award

2015

Degree Name

Master of Science

Department

Physics and Astronomy

First Advisor

Kai-ming Ho

Abstract

This thesis summarizes our study on the crystal structures prediction of Fe-V-Si system using genetic algorithm and cluster expansion. Our goal is to explore and look for new stable compounds. We started from the current ten known experimental phases, and calculated formation energies of those compounds using density functional theory (DFT) package, namely, VASP. The convex hull was generated based on the DFT calculations of the experimental known phases. Then we did random search on some metal rich (Fe and V) compositions and found that the lowest energy structures were body centered cube (bcc) underlying lattice, under which we did our computational systematic searches using genetic algorithm and cluster expansion.

Among hundreds of the searched compositions, thirteen were selected and DFT formation energies were obtained by VASP. The stability checking of those thirteen compounds was done in reference to the experimental convex hull.

We found that the composition, 24-8-16, i.e., Fe3VSi2 is a new stable phase and it can be very inspiring to the future experiments.

DOI

https://doi.org/10.31274/etd-180810-4220

Copyright Owner

Chong Chen

Language

en

File Format

application/pdf

File Size

33 pages

Included in

Physics Commons

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