Sulfides - I was asked to try to calculate stable phonons for the following BZS structures. Some of the phonon dispersion plots are good and some are bad, however, this project is on hold while I focus on my thesis project. See below (New Oxides). The progress made has been organized in a PDF and can be viewed from the link below.

• BaZrS3
• Ba2ZrS4
• Ba3Zr2S7
• SrZrS3

[Calculation Workflow Sulfide Perovskites]

Thermal Barrier Coatings - The following collection of oxide structures were found using a high-throughput first-principles calculations to satisfy criteria to be consider very good candidates for thermal barrier coatings [see paper here]. I was asked to try to use our methods to calculate the phonons and ultimately the thermal conductivity, however this project is currently stalled because my best efforts are still resulting in imaginary frequencies in the phonon dispersion plots, indicating instability in the crystal.

• BiGaO3
• EuHfO3
• EuSbO3
• TlNbO3
• TlTaO3

After struggling to get stable phonons for the previous set of oxides, I moved on to a new set of oxides. This set of oxides was shown to have stable phonons using different machine learning methods and thus we were confident we could get past this step. I have successfully calculated and created the phonon dispersion for each crystal and am pleased to report that I have been able to get all positive frequencies with only a 2x2x2 supercell. The dispersion can be viewed below in the link below. I have already calculated the thermal conductivity for a few of these crystals but am currently doing some conversion testing to ensure accuracy before I share the results.

• CsBiO3
• CsReO3
• CsSbO3
• CsWO3
• RbReO3
• RbWO3
• TlReO3

[New Oxides]

Here is summary of a broader view of the materials I have looked at.

[Phonon Dispersion] [Data Table]

From phonon results I have confirmed 4 structures that are stable: BaZrO3, BaSnO3, BaHfO3, and KTaO3. I have calculated the thermal properties for these materials. See workflow PDF's below.

[BaZrO3 Electronic Notebook] [BaSnO3 Electronic Notebook] [BaHfO3 Electronic Notebook] [KTaO3 Electronic Notebook]

Here is a copy of my master's thesis which discusses this project in extensive detail. We are still working on this project and hope to submit for publication when finalized results are completed.

[Master's Thesis]