The growth of atomically rough 4He crystals

We have studied the growth of atomically rough bcc and hcp4He crystals from the superfluid phase for temperatures T > 0.9 K. The growth coefficient displays a temperature dependence which can be represented by m4KaeAElkflTT.h e parameter AE is found to be in close agreement with the energy gap of rotons, suggesting that theqe thermal excitations dominate the growth kinetics. Besides, the absolute value of the growth coefficient depends on crystal orientation, with an anisotropy for the hcp phase of about a factor of 2.5 between the (10iO) and (0001) planes