1. Crystal-melt interfacial energy:This quantity plays an important role in the dynamics and morphological aspects of crystal growth. Yet, accurate estimation of γ is difficult and hence simulation methods are expected to play an important role. Recently, we calculated γ and its anisotropy for silicon crystal-melt interface at ambient pressure using MC simulation. Our result could explain important aspects of Czochralski method, which is the standard industrial method to produce high quality silicon crystals for the semiconductor chip manufacture. Current efforts are underway to calculate γ and its anisotropy for carbon (diamond) and for Germanium, which is again an important semiconductor material. (This work is in collaboaration with Prof. X. C. Zeng)
2.Phase diagram calculation for crystalline materials: We have developed new methods to predict melting temperature (Tm) of crystals using computer simulation for a given model potential. Our method extends naturally to binary systems and to sublimation temperature calculations. Current project include predicting Tm of (a) silicon using Stillinger-Weber (3-body) potential, (b) carbon (diamond) using Tersoff potential, and (c) binary alloys of SiGe and SiC.
3. New Applications of Bennett Acceptance Ratio (BAR) method : Despite its accuracy and numerical efficiency, BAR technique finds limited use in the literature. In many cases, BAR method provides a useful alternative to thermodynamic integration, which is the standard technique used for free energy calculations. We recently applied BAR method to γ calculations (described above). We are currently applying it to melting temperature calculations. We are also interested in extending BAR method to different statistical mechanical ensembles.