On the stability of "non-magic" endohedrally doped Si clusters: A first-principles sampling study of MSi16^+ (M =Ti,V,Cr)

Abstract

Density-functional theory is used to study the geometric and electronic structure of cationic Si16^+ clusters with a Ti, V or Cr dopant atom. Through unbiased global geometry optimization based on the basin-hopping approach we confirm that a Frank- Kasper polyhedron with the metal atom at the center represents the ground-state isomer for all three systems. The endohedral cage geometry is thus stabilized even though only VSi16^+ achieves electronic shell closure within the prevalent spherical potential model. Our analysis of the electronic structure traces this diminished role of shell closure for the stabilization back to the adaptive capability of the metal- Si bonding, which is more the result of a complex hybridization than the orginally proposed mere formal charge transfer. The resulting flexibility of the metal-Si bond can help to stabilize also "non-magic" cage-dopant combinations, which suggests that a wider range of materials may eventually be cast into this useful geometry for cluster-assembled materials.

13 pages including 5 figures; related publications can be found at http://www.fhi-berlin.mpg.de/th/th.html

References in corpus (2)

• Diamondoid Molecules
• Assessing the efficiency of first-principles basin-hopping sampling

Cited by in corpus (5)

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• Multi-Doping of Si Cages: High Spin States beyond the Single-Dopant Septet Limit
• $M$Si${}_{20}$H${}_{20}$ Aggregates: From Simple Building Blocks to Highly Magnetic Functionalized Materials
• Global Structure Search for Molecules on Surfaces: Efficient Sampling with Curvilinear Coordinates
• Enhanced magnetism of Cu${}_n$ clusters capped with N and endohedrally doped with Cr