Ab initio procedure for constructing effective models of correlated materials with entangled band structure

Takashi Miyake, Ferdi Aryasetiawan, Masatoshi Imada

Research output: Contribution to journalArticle

100 Citations (Scopus)

Abstract

In a previous work, a procedure for constructing low-energy models of electrons in solids was proposed. The procedure starts with dividing the Hilbert space into two subspaces: the low-energy part (" d space") and the rest of the space (" r space"). The low-energy model is constructed for the d space by eliminating the degrees of freedom of the r space. The thus derived model contains the strength of electron correlation expressed by a partially screened Coulomb interaction, calculated in the constrained random-phase approximation (cRPA), where screening channels within the d space, Pd, are subtracted. One conceptual problem of this established downfolding method is that for entangled bands it is not clear how to cut out the d space and how to distinguish Pd from the total polarization. Here, we propose a simple procedure to overcome this difficulty. The d space is defined to be an isolated set of bands generated from a set of maximally localized Wannier basis, which consequently defines Pd. The r subspace is constructed as the complementary space orthogonal to the d subspace, resulting in two sets of completely disentangled bands. Using these disentangled bands, the effective parameters of the d space are uniquely determined by the cRPA method. The method is successfully applied to 3d transition metals.

Original languageEnglish
Article number155134
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume80
Issue number15
DOIs
Publication statusPublished - 2009 Oct 27
Externally publishedYes

Fingerprint

Band structure
Electron correlations
Hilbert spaces
Coulomb interactions
Transition metals
Screening
Polarization
Electrons
Hilbert space
approximation
energy
electrons
screening
degrees of freedom
transition metals
polarization

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Ab initio procedure for constructing effective models of correlated materials with entangled band structure. / Miyake, Takashi; Aryasetiawan, Ferdi; Imada, Masatoshi.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 80, No. 15, 155134, 27.10.2009.

Research output: Contribution to journalArticle

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