The Library
The Korringa-Kohn-Rostoker nonlocal coherent-potential approximation : a new method for calculating the electronic structure of disordered metallic systems
Tools
Rowlands, Derwyn Andrew (2004) The Korringa-Kohn-Rostoker nonlocal coherent-potential approximation : a new method for calculating the electronic structure of disordered metallic systems. PhD thesis, University of Warwick.
|
Text
WRAP_thesis_Rowlands_2004.pdf - Submitted Version Download (5Mb) | Preview |
Official URL: http://webcat.warwick.ac.uk/record=b1746568~S1
Abstract
The limitations of the current 'first-principles' effective medium approach to calculating
the electronic structure of disordered systems are described. These limitations
can be addressed by a cluster theory, and only very recently the first satisfactory cluster
theory, the nonlocal coherent potential approximation, has been developed within
a tight-binding framework. However an approach based on KKR multiple scattering
is needed in order to treat the problem from first principles for ab-initio calculations.
In this thesis, these ideas are reformulated in terms of multiple scattering
theory and the Korringa-Kohn-Rostoker non-local coherent potential approximation
(KKR-NLCPA) is introduced for describing the electronic structure of disordered
systems. The KKR-NLCPA systematically provides a hierarchy of improvements
upon the widely used local mean-field KKR-CPA approach and includes nonlocal
correlations in the disorder configurations by means of a self-consistently embedded
cluster. The KKR-NLCPA method satisfies all of the requirements for a successful
cluster generalisation of the KKR-CPA; it determines a site-to-site translationally-invariant
effective medium, it is herglotz analytic, becomes exact in the limit of large
cluster sizes, reduces to the KKR-CPA for a single-site cluster, is straightforward to
implement numerically, and enables the effects of short-range order upon the electronic
structure to be investigated. In particular, it is suitable for combination with
electronic density functional theory to give an ab-initio description of disordered
systems. Future applications to charge correlation and lattice displacement effects
in alloys and spin fluctuations in magnets amongst others are very promising. The
method is illustrated by application to a simple one-dimensional model.
Item Type: | Thesis (PhD) |
---|---|
Subjects: | Q Science > QC Physics |
Library of Congress Subject Headings (LCSH): | Electronic structure , Cluster theory (Nuclear physics) |
Official Date: | February 2004 |
Institution: | University of Warwick |
Theses Department: | Department of Physics |
Thesis Type: | PhD |
Publication Status: | Unpublished |
Supervisor(s)/Advisor: | Staunton, Julie |
Sponsors: | Engineering and Physical Sciences Research Council |
Extent: | xiii, 97 leaves |
Language: | eng |
Request changes or add full text files to a record
Repository staff actions (login required)
View Item |
Downloads
Downloads per month over past year