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We present a scanning tunnelling microscopy (STM) investigation of Co silicide cluster and island formation on Si(111)-(7 × 7). We identify sub-nanometre clusters, which we propose to be the precursors to Co silicide nucleation and growth. The observation of metastable phases and various domains on the surface suggest significant Si rearrangement during silicide formation. Surface diffusion of both Si and type-1 clusters plays a vital role in the nucleation of Co silicide islands. With the help of density functional theory calculations, we propose a model for the surface structure of atomically flat CoSi2(111)-(2 × 2) islands.

First-principles calculations within the density functional theory (DFT) with GGA-PBE exchangecorrelation scheme have been employed to predict the structural, the elastic and the electronic properties of newly discovered lithium silicide superconductor, Li 2 PtSi 3 , for the first time. All the theoretical results are compared with those calculated recently for isostructural Li 2 IrSi 3 . The present study sheds light on the effect of replacement of transition metal element Ir with Pt on different mechanical, electronic, and superconducting properties. The effect of spin-orbit coupling on electronic band structure was found to be insignificant for Li 2 PtSi 3 . The difference in superconducting transition temperatures of Li 2 PtSi 3 and Li 2 IrSi 3 arises primarily due to the difference in electronic energy density of states at the Fermi level. Somewhat reduced Debye temperature in Li 2 PtSi 3 plays a minor role. We have discussed the implications of the theoretical results in details in this study.

Articles you may be interested inMetal-cluster growth with asymmetric diffusion and reversible aggregation on Si ( 111 ) 7 × 7

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