| Centre
| | | | | | | webmail : intra-extra| Accès VPN| Accès IST | English
Univ. Paris-Saclay
Kinetics and thermodynamics of defects, impurities, nanostructures and interfaces
Matthias Posselt
Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf
Vendredi 10/12/2010, 10:30
SRMP Bât 520 p.109, CEA-Saclay

Computer simulations using classical interatomic potentials are an efficient and promising tool to investigate and understand atomic-level properties and processes in advanced materials. They allow the consideration of length and time scales which are often hardly accessible by experiments. However, the accuracy of the interatomic potentials employed in such type of simulations determines decisively the quality of the obtained results. Therefore, these potentials must be continuously improved and evaluated.

In the present contribution three applications of atomistic computer simulations are illustrated. The focus is on kinetics, energetics and thermodynamics of defects, impurities, nanostructures and interfaces in materials for micro- and nanoelectronics and in structural materials for fission reactors.

The first example deals with molecular dynamics simulations on basic migration mechanisms of mono- and di-(self-)interstitials in Si. Both the atomic mobility due to the presence of the defect and the defect mobility itself were determined. The mechanism of di-interstitial migration depends on temperature, in contrast to that of the mono-interstitial.

In the second example amorphous Si and Ge as well as their solid-phase epitaxial recrystallization (SPER) are considered. Results obtained by different interatomic potentials are compared. The molecular dynamics simulations yield amorphous material with realistic structural and thermodynamic properties, but the SPER rate is strongly overestimated.  It is shown that a more realistic SPER rate can be obtained using a modified interatomic potential which yields a higher melting temperature of the amorphous phase. This is explained by the fact that both melting and SPER are essentially determined by the flexibility of atomic bonds.

The subject of the third example is the formation of coherent clusters containing vacancies, Cu and Ni in bcc-Fe. Using the most recent interatomic potential for Fe-Cu-Ni alloys, the structure, energetics and thermodynamics of the clusters were determined. Many clusters up to a size of 200 monomers (vacancies, Cu and Ni atoms) were studied. In the case of vacancy-Cu clusters a core-shell structure is found where Cu atoms coat the outer surface of vacancy clusters. In a vacancy-Cu-Ni cluster Ni atoms are never first nearest neighbors of vacancies, and the Ni atoms cover the Cu-surface of inner vacancy-Cu cluster. The total and monomer binding energy as well as the nucleation free energy of the clusters were calculated. The monomer binding energy is an important input parameter of rate theory and object kinetic Monte Carlo simulations. For further application in these calculations compact and physically-based fit formulae were derived from the atomistic data.

Contact : Luc BARBIER


Séminaire SRMP - Informations pratiques

Entrée sur le site du CEA de Saclay pour les séminaires SRMP

Afin de pouvoir entrer sur le site du CEA de Saclay veuillez adresser les données personnelles suivantes par courriel à :
(secrétariat) un avis d’entrée vous sera alors délivré :


Nom :

Prénom :

Date et lieu de naissance :

Nationalité :

Nom de l'employeur :


Ces informations doivent être envoyées au mieux deux jours avant la date du séminaire.>

Lors de votre venue vous devez vous présenter avec une carte d'identité ou un passeport en cours de validité. L'entrée sur le site se fait par l'entrée principale ou porte Nord (suivre le lien ci-dessous), un badge vous y sera remis. Demandez à l'accueil le Bât.520, ils vous renseigneront.
Les séminaires se déroulent au Bât. 520, pièce 109 (1er étage).
En cas de problème vous pouvez contacter le secrétariat au : 01 69 08 51 67

Formalities for entering the CEA Saclay site for SRMP seminars

To enter in CEA Saclay you need to send the following personal data to   (secretariat):

Informations utiles/Practical informations - Contact:

Informations:  Access to the CEA Saclay




Last Name :

First Name :

Place and date of birth :

Nationality :

Employer Name :

These informations must be preferably sent at least two days before the seminar date.


When you come you must have a valid ID card or passport with you.

The entrance in CEA Saclay is through the main entrance or north entrance (see link below), a pass will be delivered. Ask at the “accueil” the path for the building 520. SRMP seminars take place in room 109 (first floor).

Any questions/troubles do not hesitate to contact our secretariat: 33 (0)1 01 69 08 51 67.


#38 - Mise à jour : 11/02/2013


Retour en haut