Date Awarded

1989

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Physics

Advisor

Henry Krakauer

Abstract

The local density approximation (LDA) has been proved to be a powerful starting point for calculating electronic and structural properties for many real materials. We have studied the effects of particular forms of exchange-correlation potentials (the X{dollar}\alpha{dollar} and Hedin-Lundqvist form) upon the structural properties for the 3d Ti and 4d Zr using a highly accurate linearized augmented plane wave (LAPW) method. The calculated equilibrium volumes differ by 6-8% for these two forms (with X{dollar}\alpha{dollar} results in better agreement with experiment) with proportional differences in other structural properties, which we take to be an indication of the intrinsic reliability of the LDA. Considerable sensitivity in the calculated structural properties to the particular exchange-correlation potential (the X{dollar}\alpha{dollar}, Wigner, and Hedin-Lundqvist) was also found for the fcc and the high temperature bcc La. The calculation on SmS reveals that the LDA is inadequate for this very localized 4f electron system, while the LDA works fairly well for the chemically similar material LaS. For HgTe and HgSe, the fully occupied 5d electrons in Hg has been found to be important in determining the structural properties through the Hg d - chalcogen p interactions, however this p-d hybridization appears to be relatively unchanged through the various pressure induced phase transitions. We calculated the total energy of the seven layer slabs of Pd(111) surface as a function of the top layer spacing, the relaxation is found to be very small ({dollar}<{dollar}1%).

DOI

https://dx.doi.org/doi:10.21220/s2-mg9r-bp62

Rights

© The Author

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