Effects of cycle patterns of accelerated crucible rotation technique (ACRT) on the flows, interface, and segregation in vertical Bridgman crystal growth

The accelerated crucible rotation technique (ACRT) has been used extensively in crystal growth for the control of flow and segregation. However, the amelioration of the spin-up and spin-down flows for a favorable growth has not yet been fully understood. In this study, we investigate several ACRT schemes and discuss their effects on the flow, interface morphology, and solute segregation during the vertical Bridgman growth of succinonitrile (SCN) containing acetone. Both numerical simulation and visualization experiments are conducted. In addition to the triangular and trapezoidal patterns, stair-up, stair-down, and pulse schemes are proposed for a better flow and mixing control without much interface deformation. For all the ACRT schemes investigated here, the simulated results are in good agreement with the observed ones.