Ab Initio Atomistic Thermodynamics for Surfaces: A Primer
Abstract
Rational design and advancement in materials science will ultimately rely on an atomic-scale understanding of the targeted functionality. Corresponding modeling must then address the behavior of electrons and the resulting interactions that govern the elementary processes among the atoms and molecules. Modern electronic structure theory methods like density-functional theory (DFT) have matured, allowing a description that is often already accurate enough to allow for a modeling with predictive character. These techniques are referred to as first-principles (or in latin: ab initio) to indicate that they do not rely on empirical or fitted parameters, which then makes them applicable for a wide range of realistic conditions. A predictive modeling of materials properties requires a consistent treatment in the wide hierarchy of scales from the electronic level to macroscopic lengths and times. The central idea of ab initio atomistic thermodynamics is to employ the information on the potential energy surface provided by modern electronic structure theories, in order to calculate appropriate thermodynamic potential functions. With the latter, macroscopic system properties at finite temperatures can immediately be discussed. At surfaces, such a thermodynamic description can be particularly useful, since it provides the possibility to suitably divide the total system into smaller subsystems that are mutually (or partly) in equilibrium with each other. This way, infinite, but homogeneous parts of the system like bulk or surrounding gas phase can be efficiently represented by corresponding reservoirs, which e.g. allows to address surfaces in contact with realistic environments. In this tutorial text we have focused on a very simple realization of this general scheme, namely the direct screening approach, to determine the equilibrium geometry and composition of a solid surface in contact with a given environment at finite temperature and pressure.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2006
- Accession Number
- ADA476575
Entities
People
- Jutta Rogal
- Karsten Reuter