Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 36: Methods: Atomic and electronic structure

O 36.3: Vortrag

Dienstag, 23. März 2010, 15:30–15:45, H34

Modeling of interfaces and nanostructures: Effects of structure mismatch, bond polarity and interface charges — •Roman Leitsmann — GWT-TUD mbH, Material Calculations, Chemnitz, Germany

The characterization of interface and nanostructure properties versus dimension is of increasing importance [1]. Combinations of strongly ionic semiconductors such as PbTe and CdTe crystallizing in different structures may serve as prototypical systems. However, the theoretical ab initio description of interfaces between polar materials is controversially discussed in the literature [1].

We use ab initio methods to investigate structural and electronic properties of PbTe/CdTe interfaces and nanostructures. For this purpose 4 supercell schemes have been developed to treat internal electric fields, stoichiometry, orientation and thereby to model different experimental situations. The advantages and disadvantages of these models will be discussed at the prototypical example of PbTe/CdTe systems. The obtained interface energies are applied to PbTe nanodots embedded in a CdTe semiconductor matrix. For this system we predict an equilibrium rhombo-cubo-octahedron shape. It is used to show that the special arrangement of polar dot-matrix interfaces induces an electrostatic field, which strongly influences the geometrical and electronic properties and reduces the symmetry of the system [3].

[1] APL 88, 192109 (2006), NJP 8, 317 (2006); [2] PRB 79, 235331 (2009); [3] PRB 78, 205324 (2008), PRB accepted (2009)