Affordable Access

Publisher Website

LEED investigation of temperature-dependent surface order of Pb single crystal surfaces

Surface Science
Publication Date
DOI: 10.1016/0039-6028(89)90737-1


Abstract The intensities of several LEED beams from clean Pb(110) and Pb(111) surfaces have been measured in the temperature range from 200 to 590 K and 585 K, respectively. For Pb(111) the intensities show a normal Debye-Waller type decrease with increasing temperature up to 585 K, where LEED spots are still visible. For Pb(110), on the other hand, an additional intensity drop is seen at 490 K and above indicating an order-disorder phase transition. The intensity behavior for (10) and (01) beams of Pb(110) is distinctly different in the sense that disordering along the [11̄0] direction is faster than along [001]. This anisotropy in disorder remains visible up to 590 K. where the (01) beam still has residual intensity whereas the (10) beam is indistinguishable from the background. A quantitative evaluation suggests that the phase boundary in the [11̄0] direction is atomically sharp while that in the [001] direction is fairly diffuse. The evaluation is carried out in terms of an anisotropic order parameter function.

There are no comments yet on this publication. Be the first to share your thoughts.