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Green's function multiple-scattering theory with a truncated basis set: An augmented-KKR formalism

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Title Green's function multiple-scattering theory with a truncated basis set: An augmented-KKR formalism
 
Creator ALAM, A
KHAN, SN
SMIRNOV, AV
NICHOLSON, DM
JOHNSON, DD
 
Subject CONSISTENT ELECTRONIC-STRUCTURE
NI-ZN SYSTEM
RANDOM ALLOYS
TOTAL-ENERGY
AB-INITIO
INCOMMENSURATE
COMMENSURATE
DENSITY
IRON
 
Description The Korringa-Kohn-Rostoker (KKR) Green's function, multiple-scattering theory is an efficient site-centered, electronic-structure technique for addressing an assembly of N scatterers. Wave functions are expanded in a spherical-wave basis on each scattering center and indexed up to a maximum orbital and azimuthal number L-max = (l, m)(max), while scattering matrices, which determine spectral properties, are truncated at L-tr = (l, m) tr where phase shifts delta l> l(tr) are negligible. Historically, L-max is set equal to L-tr, which is correct for large enough L-max but not computationally expedient; a better procedure retains higher-order (free-electron and single-site) contributions for L-max > L-tr with delta(l)> l(tr) set to zero [X.-G. Zhang andW. H. Butler, Phys. Rev. B 46, 7433 (1992)]. We present a numerically efficient and accurate augmented-KKR Green's function formalism that solves the KKR equations by exact matrix inversion [R-3 process with rank N(L-tr + 1) 2] and includes higher-L contributions via linear algebra [R-2 process with rank N(l(max) + 1) 2]. The augmented-KKR approach yields properly normalized wave functions, numerically cheaper basis-set convergence, and a total charge density and electron count that agrees with Lloyd's formula. We apply our formalism to fcc Cu, bcc Fe, and L1(0) CoPt and present the numerical results for accuracy and for the convergence of the total energies, Fermi energies, and magnetic moments versus L-max for a given L-tr
 
Publisher AMER PHYSICAL SOC
 
Date 2014-12-28T13:15:05Z
2014-12-28T13:15:05Z
2014
 
Type Article
 
Identifier PHYSICAL REVIEW B, 90(20)
1098-0121
1550-235X
http://dx.doi.org/10.1103/PhysRevB.90.205102
http://dspace.library.iitb.ac.in/jspui/handle/100/16695
 
Language English