Valence Bond Cluster Studies of Alkali Metal/Semiconductor Bonding
PENNSYLVANIA UNIV PHILADELPHIA DEPT OFPHYSICS
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We present results of cluster studies of alkali metalsemiconductor bonding. Using the Generalized Valence Bond GVE method, we find a remarkable consistency in the behavoir of bonding orbitals for a variety of systems, including LiH, CLi4, LiH4 and several hypervalent systems, such as SiH3Li2, SiH4Li2. Our results show that the metal-semiconductor bonding in these systems can be understood in terms of a pairing between McAdon-Goddard type metallic bonding orbitals and a set of equivalent orbitals of the non-metallic species. We propose that the results are relevant to the initial stages of alkali overlayer growth on semiconductor surfaces and lead to a simple picture of the bonding including the transition from a non-conducting to a conducting layer. We have considered numerous proposed hypervalent structures in light of the above results and find that they can be understood.
- Physical Chemistry