Metallization of Ge(001)-p(2 x 1) surface as result of thermal fluctuations

摘要

We present a theoretical study of the metallization of Ge(001)-p(2 x 1) surface which is observed in experimental data. We have considered the connection between thermal fluctuation of this surface structure and its metallic properties. To this end we have performed long-time MD-DFT simulations. The obtained results show that thermal fluctuation of the Ge(001)-p(2 x 1) structure may cause its metallization which in not necessary connected with a flip-flop motion of dimer atoms. It was shown that the metallization of the Ge(001)-p(2 x 1) surface takes place when the dimer buckling angle is reduced to around 11 degrees. In the case of our simulations the considered surface system remained in the metallic state for 25% of the simulation time. We have also found that the metallic state of the fluctuating Ge(001)-p(2 x 1) surface is built up by dangling bonds of the dimer atoms shifted up (D-up) and down (D-down). (c) 2006 Elsevier B.V. All rights reserved.