The Fermi contact contribution to the Knight shift in Be from self-consistent spin-polarized calculations

1981 ◽  
Vol 59 (4) ◽  
pp. 585-595 ◽  
Author(s):  
L. Wilk ◽  
M. Nusair ◽  
S. H. Vosko
Keyword(s):  
Fermi Surface ◽  
Spin Density ◽  
Knight Shift ◽  
Density Functional ◽  
Local Spin Density Approximation ◽  
Functional Formalism ◽  
Spin Polarized ◽  
Valence Electrons ◽  
Self Consistent ◽  
Fermi Contact

The linear augmented plane wave method in the muffin-tin approximation was used to perform self-consistent spin-polarized calculations of the electron number density n(r) and spin (magnetic moment) density m(r) in metallic Be, within the framework of the spin density functional formalism. For the exchange-correlation functional we used the recent accurate results of Vosko et al. in the local spin density approximation. The Fermi contact contribution to the Knight shift is proportional to the sum of three spin densities (evaluated at the nucleus) arising from (i) the valence electrons at the Fermi surface, (ii) the core electrons, and (iii) the valence electrons below the Fermi surface. We find a 90% cancellation between (i) and (ii) which greatly magnifies the significance of the relatively small effect (iii). Although our contact term is still positive in sign, its magnitude is nearly one-fourth of the previous smallest first principles result and thus requires a smaller orbital diamagnetic contribution than previously invoked to explain the negative experimental value of the Knight shift.

A theoretical study of the Knight shift and its volume dependence for Li, Na, and K

1981 ◽  
Vol 59 (7) ◽  
pp. 888-896 ◽  
Author(s):  
L. Wilk ◽  
S. H. Vosko
Keyword(s):  
Fermi Surface ◽  
Spin Density ◽  
Density Functional ◽  
Correlation Energy ◽  
Energy Functional ◽  
Local Spin Density Approximation ◽  
Functional Formalism ◽  
Core Electron ◽  
The Core ◽  
Volume Dependence

The augmented plane wave method, in the muffin-tin approximation, was used to perform self-consistent spin-polarized calculations of the electron number densities, n(r), and spin magnetic moment densities, m(r), within the framework of the spin density functional formalism. For the exchange-correlation energy functional we used the new improved results of Vosko and coworkers in the local spin density approximation. The calculations were carried out for the range of volumes 0.9 ≤ V/V0 < 1. The contributions to the total Fermi contact term, m(0), relative to the Fermi surface contribution, were approximately −24, −2, and −2% from the core electron polarization and −0.7, −5, and −6% from the polarization of the valence electrons below the Fermi surface, for Li, Na, and K respectively. In Li the volume dependence of m(0) was strongly affected by the volume dependence of the core contribution, which differed markedly from that of the Fermi surface contribution. In both Li and K the calculated volume dependence for small volume changes was in good agreement with recent experiments, while in Na the trend was correct but the slope of the curve was too large. In all cases the results were very sensitive to achieving a high degree of self-consistency. The absolute values of m(0) are in excellent agreement with the measured Knight shifts.

Total energies in rubidium and cesium clusters

1990 ◽  
Vol 68 (10) ◽  
pp. 1129-1133 ◽  
Author(s):  
B. N. Onwuagba
Keyword(s):  
Spin Density ◽  
Shell Structure ◽  
Density Functional ◽  
Local Spin Density Approximation ◽  
Density Approximation ◽  
Functional Formalism ◽  
Local Spin ◽  
Total Energies

The total energies in rubidium and cesium clusters are investigated as functions of the number of atoms in a cluster in the framework of the local spin density approximation to the density functional formalism. The computed results provide useful information regarding the role played by the shell structure and predict the experimental spectra in rubidium and cesium clusters.

Magnetic Properties of Embedded Rh Clusters in Ni Matrix

1995 ◽  
Vol 384 ◽  
Author(s):  
Zhi-Qiang Li ◽  
Yuichi Hashi ◽  
Jing-Zhi Yu ◽  
Kaoru Ohno ◽  
Yoshiyuki Kawazoe
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Magnetic Moments ◽  
Functional Formalism ◽  
Rhodium Clusters ◽  
Spin Polarized ◽  
Local Density Functional

ABSTRACTThe electronic structure and magnetic properties of rhodium clusters with sizes of 1 - 43 atoms embedded in the nickel host are studied by the first-principles spin-polarized calculations within the local density functional formalism. Single Rh atom in Ni matrix is found to have magnetic moment of 0.45μB. Rh13 and Rhl 9 clusters in Ni matrix have lower magnetic moments compared with the free ones. The most interesting finding is tha.t Rh43 cluster, which is bulk-like nonmagnetic in vacuum, becomes ferromagnetic when embedded in the nickel host.

Ground State Properties And Magnetism In Substitutionally Disordered Fe1-xCrx Alloys

1990 ◽  
Vol 186 ◽  
Author(s):  
W. A. Shelton ◽  
F. J. Pinski ◽  
D. D. Johnson ◽  
D. M. Nicholson ◽  
G. M. Stocks
Keyword(s):  
Ground State ◽  
First Principles ◽  
Correlation Energy ◽  
Local Spin Density Approximation ◽  
Density Approximation ◽  
Potential Approximation ◽  
Spin Polarized ◽  
Self Consistent ◽  
Cr Concentration ◽  
The Individual

AbstractWe have performed calculations of the electronic structure of the random substitutional bcc Fe1-xCrx alloys, using the spin-polarized, self-consistent Korringa, Kohn and Rostoker coherent potential approximation (KKR-CPA) method. This is a first principles method based on a local spin density approximation for electron exchange and correlation energy. For the iron-rich alloys, we find that the average moment decreases linearly with Cr concentration, although the individual moments show a different concentration dependence and the Cr moment is anti-parallel to the Fe moment. This system is similar to Fe1-xVx system, although some details are different.

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