CV

Curriculum vitae PDF

Research

• Postdoctoral Researcher in Multiscale Materials Modelling, Westlake University (2024-2026).
• Postdoctoral Researcher in Computational Nano-Electrochemistry, Imperial College London (2022-2024).

Education

• PhD Condensed Matter and Materials Physics, University College London (2018-2022).
• MSc. Chemistry and Molecular Physics (First class Honours), University of Nottingham (2014-2018).

Conferences and related events

• Asian Electronic Structure Workshop, 2025. Poster presentation.
• Materials and Molecular Modelling Hub, 2023. Poster presentation.
• Particles at Exascale MPI/OpenMP training, 2023.
• Supercomputer modelling of advanced materials at the Royal Society, 2022. Poster presentation.
• Psi-k, 2022. Poster presentation.
• Computational Molecular Science, 2019. Poster presentation.
• Research Group Seminar at Chicheley Hall, 2022. Oral presentation.
• Thomas Young Centre Student Day, 2019. Poster presentation.
• CP2K Users and Developers symposium at Imperial College London, 2019.
• Helsinki Winter School in Theoretical Chemistry, 2018.
• CP2K Summer School at Daresbury Laboratory, 2018.

Publications

Polaronic structure of excess electrons and holes for a series of bulk iron oxides

Ahart, C. S., Blumberger, J. & Rosso, K. M. Polaronic structure of excess electrons and holes for a series of bulk iron oxides. Phys. Chem. Chem. Phys. 22, 10699–10709 (2020).

Electron and Hole Mobilities in Bulk Hematite from Spin-Constrained Density Functional Theory

Ahart, C. S., Rosso, K. M. & Blumberger, J. Electron and Hole Mobilities in Bulk Hematite from Spin-Constrained Density Functional Theory. J. Am. Chem. Soc. 144, 4623–4632 (2022).

Implementation and Validation of Constrained Density Functional Theory Forces in the CP2K Package

Ahart, C. S., Rosso, K. M. & Blumberger, J. Implementation and Validation of Constrained Density Functional Theory Forces in the CP2K Package. J. Chem. Theory Comput. 18, 4438–4446 (2022).

Transitional surface Pt carbide formation during carbon nanotube growth

Nerl, H. C., Ahart C. S., Eljarrat, A., Koch C. T., Cucinotta C. S. & Plodinec, M. Transitional surface Pt carbide formation during carbon nanotube growth. Carbon, 228, 119399, 2024.

Enabling Ab-Initio Molecular Dynamics under Bias: The CP2K+SMEAGOL Interface for Integrating Density Functional Theory and Non-Equilibrium Green Functions

Ahart, C. S., Chulkov, S. K. & Cucinotta, C. S. Enabling Ab-Initio Molecular Dynamics under Bias: The CP2K+SMEAGOL Interface for Integrating Density Functional Theory and Non-Equilibrium Green Functions. J. Chem. Theory Comput. 2024.

Thesis

PhD Thesis (Official version):
Charge transport in bulk hematite and at the hematite/water interface.

PhD Thesis (Unofficial version with additional corrections):
Charge transport in bulk hematite and at the hematite/water interface.

Abstract:
Transition metal oxide materials have attracted much attention for photoelectrochemical water splitting, but problems remain, e.g. the sluggish transport of excess charge carriers in these materials, which is not well understood. In this thesis I will show how periodic, spin-constrained and gap-optimised hybrid density functional theory can be used to uncover the nature and transport mechanisms of excess electrons and electron holes in a widely used water splitting material, hematite (α-Fe₂O₃). I will show that upon ionisation the electron hole relaxes from a delocalized band state to a polaron localised on a single iron atom with localisation induced by tetragonal distortion of the 6 surrounding iron-oxygen bonds. This distortion is responsible for the sluggish hopping transport in bulk hematite, characterised by an activation energy of 70 meV and a hole mobility of 0.031 cm²/Vs. By contrast, the excess electron induces a smaller distortion of the iron-oxygen bonds resulting in delocalisation over two neighbouring Fe units. I will show that 2-site delocalisation is advantageous for charge transport due to the larger spatial displacements per transfer step. As a result, the electron mobility is predicted to be a factor of 3 higher than the hole mobility, 0.098 cm²/Vs, in qualitative agreement with experimental observations. Extending this analysis to the hematite/liquid water interface, I will show that both excess electrons and electron holes localise at the interface with qualitatively similar structures to bulk hematite. However, the presence of the interface breaks the symmetry present in the bulk crystal and as a result the hole mobility is expected to be greatly reduced. These calculations provide new fundamental insights essential for a better understanding of rate-limiting transport processes governing photocatalytic water splitting efficiency at the hematite/liquid water interface.