Ab initio simulations of semiconducting materials for nuclear energy production - Fabien Bruneval (CEA Saclay, France)

Fabien Bruneval, Service de Recherches de Métallurgie Physique, CEA Saclay, France

Abstract:

In a nuclear environment, the materials are subjected to a constant irradiation, which continuously modify the properties of materials:
Impurities are implanted through irradiation or nuclear fission and atoms of the materials are displaced and form self-interstitials and vacancies.
These defects may have detrimental effects on the material's properties.
On the contrary, in the electronic industry, defects and impurities may be deliberately introduced in a controlled manner in order to engineer the electrical, transport or optical properties.

However, despite their technological importance, defects are difficult to characterize experimentally. Quantum mechanical first principles calculations offer a complementary description. However, first principles calculations for defects are still challenging for several reasons: The structural models required for a converged description of a defect contain a large number of atoms and therefore make a quantum mechanical calculation computationally very expensive. Furthermore, the point defect properties are strongly affected by the exchange-correlation approximation employed in the calculations.

In a first part, I will present recent advances for the quantitative prediction of defect properties. The talk will focus on hybrid functionals and on the so-called GW [1] and Random-Phase approximations [2] of the many-body problem. The results will be exemplified with two relevant materials for the energy production: SiC for the nuclear industry [3] and semiconductors for the photovoltaic applications [4,5].

In a second part, I will present the ab initio description of the ion/matter interaction as it occurs in irradiation. Thanks to the linear-response theory, we have been able to produce the first fully converged calculations for the penetration of proton irradiation in bulk materials [7].

Vous pouvez consulter la page web de Fabien Bruneval au http://www.molgw.org/bruneval/index.html.

Cette conférence est présentée par le RQMP Versant Nord du Département de physique de l'Université de Montréal et le Département de génie physique de Polytechnique Montréal.

[1] F. Bruneval, Phys. Rev. Lett. 103, 176403 (2009).
[2] F. Bruneval, Phys. Rev. Lett. 108, 256403 (2012).
[3] F. Bruneval and G. Roma, Phys. Rev. B 83, 144116 (2011).
[4] G. Petretto and F. Bruneval, Phys. Rev. Applied 1, 024005 (2014).
[5] G. Petretto and F. Bruneval, Phys. Rev. B 92, 224111 (2015).
[7] A.A. Shukri, F. Bruneval, and L. Reining, Phys. Rev. B 93, 035128 (2016).