uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Adaptive Smearing for Brillouin Zone Integration
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
2011 (English)In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 111, no 5, 1025-1030 p.Article in journal (Refereed) Published
Abstract [en]

We suggest a simple scheme for automatically determining the width parameter of smearing methods of the Brillouin zone integration in electronic structure calculation. The scheme retains one free parameter that at any time can be eliminated by choosing a denser k-space mesh until the desired accuracy is obtained. The tests are carried out in the context of Methfessel-Paxton smearing. This adaptive Gaussian smearing (AGS) is easily implemented, variational with respect to partial occupancies and free from spurious occupancies that are negative or larger than one. Its convergence properties are similar to those obtained with the modified tetrahedron method for energy resolution of >= 0.1 meV.

Place, publisher, year, edition, pages
2011. Vol. 111, no 5, 1025-1030 p.
Keyword [en]
Brillouin zone integration, band structure methods, Gaussian smearing, magnetocrystalline anisotropy energy
National Category
Physical Sciences
URN: urn:nbn:se:uu:diva-148949DOI: 10.1002/qua.22476ISI: 000287163800012OAI: oai:DiVA.org:uu-148949DiVA: diva2:403788
Available from: 2011-03-15 Created: 2011-03-14 Last updated: 2012-08-01Bibliographically approved
In thesis
1. Theoretical Studies of Magnetism and Electron Correlation in Solids
Open this publication in new window or tab >>Theoretical Studies of Magnetism and Electron Correlation in Solids
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This work presents new development and applications of ab-initio simulation tools for material science. Focus lies on materials with strong electronic correlation and strong spin-orbit coupling. Improvements on methods for solving the impurity problem in LDA+DMFT is presented, as well as a reliant method for charge self-consistency in a LMTO based electronic structure code. A new adaptive scheme for Brillouin zone integration is developed, where we show a strong reduction of numerical noise compared to standard techniques. A reformulation of the standard LDA+U method aiming to reduce the number of free parameters is introduced. Fast and realistic reduction of the number of free parameters provides the possibility of high throughput calculations and enabled us to study a large number of compounds. An analysis method for polarization in terms of coupled multipoles, and their corresponding energy contributions is developed and applied. This led to the formulation of Katt's rules, a set of rules complementary to Hund's rules. Katt's rules applies for occupying the orbitals of an electronic shell with strong spin-orbit coupling. The analysis is also used to investigate the unconventional Uranium based superconductors URu2Si2, UPt3, UPd2Al3 and UNi2Al3, as well as the high temperature superconductor LaOFeAs. We also investigate the non-magnetic delta-phase of Plutonium, providing insight to the electronic structure and the branching ratios of 4d to 5f transitions seen in photo emission spectra.The influence of surface reconstruction on the magneto crystalline anisotropy is investigated in multilayer Fe/ZnSe, showing that Fe deposited on an unreconstructed interface strongly reduces the uniaxial component of the MAE. We provide a detailed understanding of the magnetic properties of Fe2P, opening possible routes for enhancing the MAE in this system. A general route to strong MAE in nano-laminates is presented, we apply this to propose a candidate with extremely strong anisotropy energy density, 5Fe/2W1-xReX for x=[0.6-0.8].

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. xii+70 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 920
Magnetism, Superconductivity, Electron Correlation, DMFT, DFT, Actinides, multipoles, hidden order, magnetic anisotropy
National Category
Condensed Matter Physics
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics
urn:nbn:se:uu:diva-172334 (URN)978-91-554-8337-1 (ISBN)
Public defence
2012-05-22, Siegbahnsalen, Lägerhyddsv. 1, Uppsala, 10:15 (English)
Available from: 2012-04-26 Created: 2012-04-04 Last updated: 2012-08-01Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Grånäs, Oscar
By organisation
Materials Theory
In the same journal
International Journal of Quantum Chemistry
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar

Altmetric score

Total: 187 hits
ReferencesLink to record
Permanent link

Direct link