title: Bond-counting rule for carbon and its application to the roughness of diamond (001).
abstract: Despite that carbon is tetravalent identical to silicon, first-principles calculations reveal that stable step structures on diamond (001) are entirely different from those on silicon. Moreover, pristine Si(001) is flat; pristine diamond (001) could be rough due to negative step formation energies. A generic bond-counting rule is established, which should apply to most carbon structures where sp2 and sp3 hybrids coexist: e.g., it provides a qualitative account of the step energy order without detailed calculation. Our findings agree with experimental observations.
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100080, China.
authors.forename: H X
authors.initials: HX
authors.lastname: Yang
authors.forename: L F
authors.initials: LF
authors.lastname: Xu
authors.forename: Z
authors.initials: Z
authors.lastname: Fang
authors.forename: C Z
authors.initials: CZ
authors.lastname: Gu
authors.forename: S B
authors.initials: SB
authors.lastname: Zhang