ICAMS / Interdisciplinary Centre for Advanced Materials Simulation


Ab-initio prediction of materials properties up to the melting point

Date: 01.05.2012
Time: 4:00 p.m.
Place: ADIS workshop 2012, Tegernsee, Germany

Blazej Grabowski

Phase diagrams are cornerstones of materials design. Traditional approaches to model phase diagrams su er from fundamental diculties related to experimental input (e.g., unstable phases). The emerging eld of ab initio supported phase diagrams is the unrivaled approach to a true advancement in the eld. However, while well established for the T=0 K regime, nite temperature ab initio calculations are still facing enormous challenges. In the rst part of this talk, I will present recent achievements in tackling the ab initio materials description up to the melting point. One particular example will be the prototype temperature-driven fcc to bcc transition in calcium. I show that phonon-phonon interactions, i.e., excitations beyond the typically applied harmonic picture, are crucial for the phase transition changing it by 400 K. I will further focus on the computation of the heat capacity, an important thermodynamic quantity, describing the methodological background of the various relevant contributions. In the second part of the talk, I will -by means of several interactive examples- explicitly show how we actually calculate the various contributions to ab initio thermodynamic properties. In particular, an estimation of CPU requirements will be given along with the examples to hopefully give a rough idea also to non-experts of what is feasible at present.

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