ABSTRACT
Using a persistent-embryo method and molecular dynamics simulations, we demonstrate that the metastable body-centered cubic (bcc) phase of iron has a much higher nucleation rate than the hcp phase under inner-core conditions. Thus the bcc nucleation is likely to be the first step of inner core formation instead of direct nucleation of the hcp phase. This mechanism reduces the required under cooling of iron nucleation, which provides a key factor to solve the inner-core nucleation paradox. The two-step nucleation scenario of the inner core also opens a new avenue for understanding the structure and anisotropy of the present inner core.
BIOGRAPHY
Prof. Kai-Ming Ho is a Distinguished Professor Emeritus in Liberal Arts and Sciences at Iowa State University and Senior Scientist at the Ames Laboratory. He is a world leader in photonic crystals, and his research interests also include the area of electronic and structural properties of crystals, surfaces, clusters, metallic liquid and glass systems. Prof. Ho is a fellow of the American Physical Society. Among his many awards, he received a DOE-BES Outstanding Scientific Accomplishment Award and a DOE award for Sustained Outstanding Research in Solid State Physics, in 1992 and 1996, respectively. His research also received the 2012 Aneesur Rahman Prize for Computational Physic from the American Physical Society.
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