Structure and vibrations of vicinal surfaces and field-induced structure modification: An ab initio study

Phenomena at surfaces present a difficult theoretical problem because the translational symmetry along the normal direction is lost, making the traditional theory for condensed matter systems, like the Bloch theory, inappropriate. The microscopic atomic configuration and electronic structure must be taken into account to explain the diverse phenomena on surface. To solve the Schroedinger equation with many body interactions directly is extremely difficult because of the huge number of degrees of freedom involved. In the mid 1960s, Walter Kohn discovered that the total energy of a system can be expressed as a functional of charge density and all the properties of the system at ground state can be expressed as a functional of the charge density. Thus by finding the ground state charge density, we would get all the information we wanted about the system. With this simple scheme, DFT is the perfect simulation method for condensed matter systems, especially surface systems. The task of this thesis is to use DFT to investigate structure and electronic properties on metallic surfaces. In this thesis, the methodology of DFT will be discussed including the improvements we have made in this subject. A DFT study of structural and vibrational properties of vicinal and flat metallic copper surfaces will be discussed. The piezoelectric effect on the metallic surfaces will also be discussed. The last chapter will be devoted to the study of surface structure modification induced by non-uniform surface stress. At the end I will discuss the possibility of designing surface structure by using the Scanning Tunneling Microscope (STM) or adsorbates. The second half of the last chapter is not within DFT theory, but within elastic theory and mean-field theory