Field evaporation from first principles

C. G. SANCHEZ; A. Y. LOZOVOI; A. ALAVI

MOLECULAR PHYSICS

Taylor & Francis Group Ltd

Año: 2004 vol. 102 p. 1045 - 1045

0026-8976

nder the application of a strong electric field, atoms from a metal surface can rupture theirbonds and escape, leading to ‘field-evaporation’. We present a first-principles description ofthis phenomenon, taking as an example the evaporation of Al adatoms from an Al(111)surface. The ‘charged-plane’ method [LOZOVOI, A. Y., and ALAVI, A., 2003, Phys. Rev. B, 68, 246416.] has been implemented in the context of a localized-basis code (SIESTA). This enables appreciable fields to be stably and efficiently applied to surfaces, represented using slabgeometries. We quantify details of the evaporation process as a function of the applied fieldstrength. The field at which the zero-temperature barrier disappears (evaporation field) ispredicted and possible scenarios of the evaporation of surface atoms are discussed. Resultsare compared to the ‘image-hump’ model for this process. The field dependence of the barrieris described by this model surprising