ABSTRACT
A striking feature of the IBS I3FeSb crystals, particularly of those buried in the silicon substrate, is the presence of lamellar domains in the silicide grains [2, 4, 5]. These domains were ultra-thin plates ofthe 13 phase which are 90° to each other around [100]13. A grow-in mechanism for the formation of the domain boundaries was proposed [2]. They were defmed as order domains (ODs), as the [010]13 and [001]13 directions are geometrically nearly identical and chemically different [2]. Fig. 2 shows a high resolution image showing the atomic-level flat interface between these domains. It is noticed that some of the domains have thickness of only half of the unit cell length in the [100]13 direction (indicated by arrows). It is worth mentioning that the 13 phase demonstrates a layered structure in the [100] direction, which is mechanically the weakest [5]. Growth in the [I 00]13 direction is naturally the slowest , due to the expected low surface energy of the (I 00)13 plane. While such lamellar domains are usually present in IBS I3FeSh, they tend to lose the lamellar feature in the surface 13 layer fabricated by RDE [11].
