Epitaxially stabilized structures of ultrathin iridium silicide

Iridium silicide formed by a solid state reaction between 500 and 950° C generally crystallizes as Ir₃Si₅ in a monoclinic structure. Our observations, however, show that below a critical thickness of the initial iridium layer of about 2 nm, a new structure can be stabilized epitaxially. On Si(001) we observe a fluorite structure. On Si(111) we observe a derivative structure of the fluorite structure. Additionally a superstructure on the basis of the fluorite structure was found.