Structural and dynamic evolution in liquid Au-Si eutectic alloy by ab initio molecular dynamics
PHYSICAL REVIEW B, cilt.81, sa.14, 2010 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 81 Sayı: 14
- Basım Tarihi: 2010
- Doi Numarası: 10.1103/physrevb.81.140202
- Dergi Adı: PHYSICAL REVIEW B
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
- Hacettepe Üniversitesi Adresli: Hayır
Özet
We report the results of first-principles molecular-dynamics simulations for liquid and undercooled eutectic Au81Si19 alloys at various temperatures. Through comparisons between Au81Si19 and Au liquids, we show the strong effects of Si alloying on the atomic-scale structure, namely the occurrence of a well-defined chemical short-range order and the slowing of the formation of icosahedral local motifs as a function of temperature. Such a behavior may explain the stability of the liquid phase at the eutectic composition by an enhancement of AuSi interactions. In examining the dynamic properties of both systems, we demonstrate a strong interplay between these structural changes and the evolution of diffusivity at low temperatures. All these results yield a possible scenario for the occurrence of such an unusual deep eutectic point.