Dresden 2011 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

DF: Fachverband Dielektrische Festkörper

DF 10: Nano- and microstructured dielectrics

DF 10.5: Talk

Wednesday, March 16, 2011, 12:00–12:20, MÜL Elch

Computation of dielectric permittivities: comparison of different crystal structures, amorphous systems and nanocomposites — •Andreas Leschhorn and Herbert Kliem — Universität des Saarlandes , Lehrstuhl für Grundgebiete der Elektrotechnik , Campus A5 1 , 66041 Saarbrücken

We investigate the influence of the microscopic structure on the dielectric properties of a dielectric material. To that, effective dielectric permittivities of a system of induced dipoles are simulated numerically on a microscopic scale by calculating the local electric fields. In contrast to macroscopic calculations the method of local fields considers all dipolar fields within the sample taking account of the electrodes by the method of images. In this way all depolarizing fields in inhomogeneous samples are regarded.

Results for amorphous dielectrics and materials with different crystal structures are compared. For example, we found that a fcc structure leads to a higher relative permittivity than a sc lattice at the same parameters. Here the product n α of particle density n and polarizability α has been kept constant. Another example is the calculation of the permittivity of a bcc structure which also exhibits a higher value than a comparable sc structure. Also the permittivity of dielectrics consisting of atoms with different polarizabilities is computed. Furthermore, nanocomposites are investigated, with regions of different structures and species of atoms.