title: Two-stage rotation mechanism for group-V precursor dissociation on Si(001).
abstract: We report ab initio identification of initial dissociation pathways for Sb4 and Bi4 tetramer precursors on Si(001). We reveal a two-stage double piecewise rotation mechanism for the tetramer to ad-dimer conversion involving two distinct pathways: one along the surface dimer row via a rhombus intermediate state and the other across the surface dimer row via a rotated rhombus intermediate state. These two-stage double piecewise rotation processes play a key role in lowering the kinetic barrier by establishing and maintaining energetically favorable bonding between adatoms and substrate atoms. These results provide an excellent account for experimental observations and elucidate their underlying atomistic origin that may offer useful insights for other surface reaction processes.
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Jian-Tao
authors.initials: JT
authors.lastname: Wang
authors.forename: Changfeng
authors.initials: C
authors.lastname: Chen
authors.forename: E G
authors.initials: EG
authors.lastname: Wang
authors.forename: Ding-Sheng
authors.initials: DS
authors.lastname: Wang
authors.forename: H
authors.initials: H
authors.lastname: Mizuseki
authors.forename: Y
authors.initials: Y
authors.lastname: Kawazoe