Buckling of Si and Ge (111)2×1 Surfaces

Triangular Mott-Hubbard insulator phases of Sn/Si(111) and Sn/Ge(111) surfaces.

The ground state of Sn/Si(111) and Sn/Ge(111) surface alpha phases is reexamined theoretically, based on ab initio calculations where correlations are approximately included through the orbital dependence of the Coulomb interaction (in the local density+Hubbard U approximation). The effect of correlations is to destabilize the vertical buckling in Sn/Ge(111) and to make the surface magnetic, wi...

Buckling and band gap of the Ge(111)2×1 surface studied by low-temperature scanning tunneling microscopy

Low-temperature scanning tunneling microscopy is used to study the 2×1 reconstruction of cleaved Ge(111) surfaces. Buckling of the surface atoms is investigated by observations of the corrugation shift between filled and empty states. In the direction, the shift in corrugation maxima from filled to empty states is found to be negative, consistent with expectations for the “negatively buckled" m...

Influence of strain on diffusion at Ge„111... surfaces

The measurement of the density of two-dimensional islands by scanning tunneling microscopy after submonolayer growth is used to determine the strain dependence of surface diffusion. Templates of strained and relaxed Ge surfaces with the same surface reconstruction are prepared for comparison. The diffusion barrier for Ge and Si adatoms is found to increase with increasing compressive strain of ...

Vibrational dynamics and band structure of methyl-terminated Ge(111).

A combined synthesis, experiment, and theory approach, using elastic and inelastic helium atom scattering along with ab initio density functional perturbation theory, has been used to investigate the vibrational dynamics and band structure of a recently synthesized organic-functionalized semiconductor interface. Specifically, the thermal properties and lattice dynamics of the underlying Ge(111)...

Scanning Tunneling Microscopy and Photoelectron Spectroscopy Studies of Si(111) and Ge(111) Surfaces: Clean and Modified by H or Sn Atoms