Stability and electronic structure of Ge(1 0 5)1 × 2: a firstprinciples theoretical study
Abstract
We studied stability and electronic structure of the Ge(1 0 5)1 × 2 surface by density functional theory (DFT) calculations. We show that the (0 0 1) surface is more stable than the (1 0 5) surface if the inplane lattice constant is equal to the equilibrium lattice constant of Ge ( a_{Ge}), while (1 0 5) becomes much more stable than (0 0 1) when the inplane lattice constant is compressed to a_{Si}. This stability change is in agreement with experimental observations that Ge(1 0 5) is stable on the Si substrate, and the reason can be explained from the differences in the surface bond lengths of the two surfaces. Because the GeGe length is considerably elongated near the Ge(1 0 5) surface, the surface bond lengths approach their equilibrium values by compressing the inplane lattice constant from a_{Ge} to a_{Si}, and (1 0 5) becomes fairly stable. Band calculations revealed that the gap between occupied and unoccupied surface states are quite large, suggesting the stability of the surface.
 Publication:

Surface Science
 Pub Date:
 February 2005
 DOI:
 10.1016/j.susc.2004.12.001
 Bibcode:
 2005SurSc.576...61H