Possible burst-like facet growth mode at high temperatures

A decade ago, a burst-like growth mode of c-facets of 4He crystals growing at mK temperatures, characterized by the alternation of time intervals during which the facet does not advance with the intervals of its fast advancement, was found [J.P. Ruutu, P.J. Hakonen, A.V. Babkin, A.Y. Parshin, J.S. Penttilä, J.P. Saramäki, G. Tvalashvili, Phys. Rev. Lett. 76 (1996) 4187]. We investigate the possibility that a similar facet growth mode exists for facets at high growth temperatures. We have applied the digital laser interferometry for monitoring facet kinetics of spherical copper selenide single crystals during their growth at constant volume growth rate around 800 K. Our analysis of directly measured (1 1 1) facet advancement curves has revealed that they consist of time intervals during which the facet does not advance vertically alternating with the time intervals of enhanced growth, resembling the burst-like facet growth mode. The results are discussed in terms of the enhancement of the local supersaturation induced by the existence of nucleation barrier.