| Abstract Scope |
In recent publications, we predicted self- and impurity diffusion coefficients through first-principles calculations based on the transition state theory [1] and a five-frequency model [2]. The free energy of vacancy formation and vacancy impurity binding is obtained through total energy and phonon calculations. Various jump frequencies are evaluated from phonon vibrational frequencies at the equilibrium and transition states when the vacancy is present. More recently, we proposed a new first-principles approach to treat the unstable vibrational mode of transition states [3]. It particularly allows one to determine the entropy of migration and the characteristic vibrational frequency, along with their temperature dependences. In this presentation, above results will be discussed.
1. Mantina et al., "First-principles calculation of self-diffusion coefficients," Phys. Rev. Lett., Vol.100, 2008, 215901.
2. Mantina et al., “First-Principles Impurity Diffusion Coefficients”, Acta Mater., (accepted, May 2009)
3. Mantina et al. “First-principles Approach to Transition States of Diffusion,” submitted |