Date of Award

2022-08-01

Degree Name

Master of Science

Department

Physics

Advisor(s)

Jorge A. Munoz

Abstract

Classical molecular dynamics methods can accurately describe a broad set of many-atomssystems. Although more economical, the results given by this framework lack the precision capable of density functional theory (DFT). Therefore, the structural stability of the B2 phase of a body-centered-cubic iron-vanadium (FeV) alloy using DFT on the electronic structure level is analyzed to verify and further explain classical results obtained by our group in this same alloy. Using Quantum Espresso and Phonopy for the computational simulations, the plotted band structure, electronic density of states (eDOS), phonon dispersions, charge density, and Fermi surfaces for various compressed unit cells are presented. The results obtained with PBE and PBEsol pseudopotentials show similarities in their trends. However, the predicted parameters do not match, as seen in the high-pressure phase transition, which is different by 20 GPa between PBE and PBEsol. The eDOS and band structure display shiftings at the Fermi energy, meaning more electrons are available to screen the ions' movement. A comparison between density functional perturbation theory (DFPT) and DFT results is made, and although the predicted outcome coincides, the way the transitions appear differs from one another. Furthermore, the transition consequence in the electrons is presented as a redistribution of charge in the second nearest neighbors of vanadiums in the interstitial sites which may have a role explaining the difference between the pressure predicted by DFT and the available experimental results at lower vanadium concentrations.

Language

en

Provenance

Received from ProQuest

File Size

67 p.

File Format

application/pdf

Rights Holder

Homero Reyes Pulido

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