TY  - JOUR
AU  - Stasevich, T. J.
AU  - Gebremariam, H.
AU  - Einstein, T. L.
AU  - Giesen, M.
AU  - Steimer, C.
AU  - Ibach, H.
TI  - Low-temperature orientation dependence of step stiffness on {111} surfaces
JO  - Physical review / B
VL  - 71
IS  - 24
SN  - 1098-0121
CY  - College Park, Md.
PB  - APS
M1  - PreJuSER-46084
SP  - 245414
PY  - 2005
N1  - Record converted from VDB: 12.11.2012
AB  - For hexagonal nets, descriptive of {111} fcc surfaces, we derive from combinatoric arguments a simple, low-temperature formula for the orientation dependence of the surface step line tension and stiffness, as well as the leading correction, based on the Ising model with nearest-neighbor (NN) interactions. Our formula agrees well with experimental data for both Ag and Cu{111} surfaces, indicating that NN interactions alone can account for the data in these cases (in contrast to results for Cu{001}). Experimentally significant corollaries of the low-temperature derivation show that the step line tension cannot be extracted from the stiffness and that with plausible assumptions the low-temperature stiffness should have six-fold symmetry, in contrast to the three fold symmetry of the crystal shape. We examine Zia's exact implicit solution in detail, using numerical methods for general orientations and deriving many analytic results including explicit solutions in the two high-symmetry directions. From these exact results we rederive our simple result and explore subtle behavior near close-packed directions. To account for the three-fold symmetry in a lattice gas model, we invoke an orientation-dependent trio interaction and examine its consequences.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000230276900104
DO  - DOI:10.1103/PhysRevB.71.245414
UR  - https://juser.fz-juelich.de/record/46084
ER  -