Martensitic transformations are solid to solid displacive modifications of the crystal order that imply a coordinated movement of a large number of atoms. They can be induced by an applied stress (e.g., pressure) or temperature change. For certain transformations, for example the transformation in iron under pressure at 15 GPa (transition from cubic centered to hexagonal compact), an important disagreement exists between simulations by electronic structure calculations (through an ab-initio simulation technique) and experience [1].

This disagreement is possibly due to the presence of crystal defects called dislocations in real crystal, which act as initial seed that significantly lower the transition threshold.
The subject of this post-doctoral internship is to set up the tools enabling the simulation of martensitic phase transitions in the presence of a dislocation by a simulation of an ab initio electronic structure. The transition at 15 GPa in iron will be studied with a screw dislocation as the initial germ. The introduction of special boundary conditions (Green's function method,[2-3]) will be considered.

[1] Dupe et al, PRB, 87, 024103, (2013)
[2] Woodward and Rao, PRL 88, 216402, (2002)
[3] Woodward et al, PRL 100, 045507, (2008)

Presentation of CEA:

The French Alternative Energies and Atomic Energy Commission (CEA) is a key player in research, development and innovation in several areas including fundamental research in the physical sciences. The CEA is established in nine centers spread throughout France. It works in partnership with many other research bodies, local authorities and universities. Bruyères le Châtel center hosts 2000 research scientists and engineers with expertise in environmental monitoring, large instruments (accelerators, lasers), materials and high performance supercomputing.

Requirements:
Good knowledge of quantum mechanics, density functional theory and interest in writing computer code is an advantage.

Application:
To apply, send a CV, a motivation letter and the contact details of two referees to  [email protected] and [email protected]