Understanding the Earth’s cores: benchmarking the ELASTIC toolkit for core-forming materials

Theme: Solid Earth Dynamics

Primary Supervisor:

Lidunka Vočadlo

Earth Sciences, UCL

Lidunka Vočadlo's Profile Picture

Secondary Supervisor:

John Brodholt

Earth Sciences, UCL

John Brodholt's Profile Picture

Project Description:

Core formation and evolution models are fundamentally dependent upon the elastic properties of planetary-forming materials under extreme conditions of pressure and temperature. Obtaining such elastic properties of materials within the atomistic framework is typically undertaken by implementing two distinct methods. Firstly, the strain-energy approach that resolves the total energies of strained crystal structures, and secondly, the strain-stress approach that resolves the stresses resulting from the applied strains. Such approaches are both mathematically rigorous and conceptually straightforward, yet the scope of their implementation is often curtailed by the large number of calculations required to derive a set of elastic constants for just a single point in P-T space. Recently, however, a new toolkit, ‘ELASTIC’, has been developed, which automates the stress-strain method by solving a system of overdetermined linear equations directly under constant pressure dynamics (NPT, NPH, etc.) within the strain-stress method, thereby significantly reducing the number of required calculations.

This project will benchmark the ‘ELASTIC’ toolkit against traditional approaches for iron and iron alloys. All atomistic calculations performed within this project will be solved using density functional theory as implemented by VASP as well as the parametrised interatomic potentials as implemented by LAMMPS.

Upon the successful completion of this project, the student will have assessed the validity of the ‘ELASTIC’ toolkit as well as the quality of various parameterised interatomic potentials when compared to density functional theory. The work outlined in this project will give the student experience of modern computational techniques and will significantly contribute to furthering our ability to readily determine fundamental properties of planetary interiors.

Policy Impact of Research:

Testing a tool that could allow the determination of physical properties to be undertaken far more easily and quickly than in the past, thus enabling a better understanding of the structure, composition and evolution of the Earths core.

Stay informed

Click here to subscribe to our RSS newsletter by email.

Find Us

University College London is the administrative lead.

North-West Wing, UCL, Gower Street, London, WC1E 6BT

Follow us on Twitter