Dresden 2014 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 59: Computational Materials Modelling IX - Ferroelectrics

MM 59.6: Vortrag

Donnerstag, 3. April 2014, 17:15–17:30, IFW D

Crystal structure prediction of materials in the BCNOP system at high pressure — •Zamaan Raza and Marco Saitta — Université Pierre et Marie Curie, Paris, France

The structure and properties of crystals containing light elements with no d- and f-electrons is often thought to be well understood, yet they frequently display unexpected characteristics when subjected to high pressures. We study the formation of novel binary and ternary compounds in the BCNOP system, at a wide range of temperatures and pressures. Examples of such systems include the ternary B-N-O, B-C-O and C-N-O systems, which are poorly understood even at ambient conditions.

In this work, we seek a better understanding of the physical and chemical phenomena occurring at high temperatures and pressures in such systems of light elements, and search for novel phases with industrially important properties, such as superhardness, superconductivity and high energy density. This presentation focuses on the theoretical side, and on what is regarded as one of the most difficult problems in the physical sciences, crystal structure prediction. The problem arises from the fact that the configurational space increases exponentially in size with the number of atoms in the system, making searches for the ground state on most potential energy surfaces intractable. To this end, we use two different approaches towards structure prediction, namely random structure searching using the AIRSS method (J. Phys. Condens. Mat. 23:53201, 2011) and evolutionary algorithms as implemented in the USPEX suite (Comp. Phys. Comm. 175:713, 2006).