Proof of the ionic character of the interaction of K with Si(100): A cluster model study

The nature of the bonding of K chemisorbed on Si(100) has been determined from analyses of ab initio electronic wavefunctions for clusters which model K./Si(100), In contrast to many recent claims, several different criteria provide totally consistent, and definitive evidence that this is an ionic bond; covalent effects are negligible. This finding is essential for understanding surface metallization of semiconductors. Furthermore, consequences of the ionic bond for the vibrational spectra of K/Si(100) are predicted and await experimental verification.