Is the elongation of Ge huts in the low-temperature regime governed by kinetics?

Contrary to pyramids and domes, elongated huts on a Si(001) substrate are commonly considered as kinetically limited structures. In this work, however, based on detailed scanning tunneling microscopy observations of Ge huts growing on Si(001) at temperatures below 550°C and finite element analysis, the possibility of an equilibrium-driven elongation is raised, where hut-preceding pits are thought to lift the energetic degeneracy of {105} facets and cause elongation along energetically preferred directions.