Lattice relaxations and hyperfine fields of heavy impurities in Fe

Korhonen, T.; Settels, A.; Papanikolaou, N.; Zeller, R.; Dederichs, P. H.

doi:10.1103/physrevb.62.452

Cited by 32 publications

(37 citation statements)

References 36 publications

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“…The later approach avoids the problem of interacting impurities in a periodic system and proved to be very powerful and flexible in the past. In particular lattice distortions can be accounted for by the so-called U-transformation technique [8]. In practice, however, this approach is limited to relatively small lattice distortions of a few percent with respect to the nearest neighbour distance.…”

Section: Theoretical Frameworkmentioning

confidence: 99%

Hyperfine Fields of Light Interstitial Impurities in Ni

et al. 2004

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The magnetic hyperfine interaction of light interstitial impurities in Ni have been studied by means of the Korringa-Kohn-Rostoker (KKR) band structure method. This method allows to deal with the impurity problem by solving the corresponding Dyson equation for the Green's function. It also allows to account for lattice relaxations. For this purpose a new technique was developed that allows to handle in principle arbitrary lattice distortions. Corresponding calculations have been performed for the magnetic hyperfine fields of the light interstitial impurities H to Ne in Ni. By minimising the force on the nearest neighbour host atoms their equilibrium position was determined. The resulting hyperfine fields for the equilibrium configuration are found to be in rather good agreement with available experimental data.

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Section: Theoretical Frameworkmentioning

confidence: 99%

Hyperfine Fields of Light Interstitial Impurities in Ni

et al. 2004

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“…For the impurity calculations we perform the self-consistent calculations for NiCrSi and produce the Green function for the bulk compound. 75,76 Then we consider a cluster of 65 atoms surrounding the Si site embedded in an infinite NiCrSi bulk crystal and calculate the electronic structure of the atoms in this cluster in real space considering a Cr atom at the central Si site. (We have to note here that we have neglected the relaxation of the atomic positions within the cluster due to the impurity atom, which is very tedious computationally, since we expect them to be small due to the high symmetry of the crystal and an extensive study of impurities is out of the scope of the present manuscript.)…”

Section: A Defects Conserving the Half-metallicitymentioning

confidence: 99%

“…Moreover Dyson equation makes possible the study of single impurities within the framework of FSKKR in real space. 75,76 In both cases we employed the local-spin-density approximation (LSDA) 77 for the exchange-correlation energy within the framework of the density functional theory. 78,79 Semi-Heusler alloys (also known as half-Heusler compounds) crystallize in the C1 b structure which consists of four fcc sublattices and have the chemical formula XYZ where X a high-valent transition metal atom, Y a lowvalent transition metal atom and Z a sp atom.…”

Section: Description Of Present Calculationsmentioning

confidence: 99%

Ab initio electronic and magnetic properties of half-metallic NiCrSi and NiMnSi Heusler alloys: The role of defects and interfaces

Galanakis

Özdoğan

Şaşıoğlu

2008

Journal of Applied Physics

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Using state-of-the-art first-principles calculations we study the properties of the ferromagnetic Heusler compounds NiYSi where Y stands for V, Cr or Mn. NiCrSi and NiMnSi contrary to NiVSi are half-metallic at their equilibrium lattice constant exhibiting integer values of the total spin magnetic moment and thus we concentrate on these two alloys. The minority-spin gap has the same characteristics as for the well-known NiMnSb alloy being around ∼1 eV. Upon tetragonalization the gap is present in the density of states even for expansion or contraction of the out-of-plane lattice parameter by 5%. The Cr-Cr and Mn-Mn interactions make ferromagnetism extremely stable and the Curie temperature exceeds 1000 K for NiMnSi. Surface and interfaces with GaP, ZnS and Si semiconductors are not half-metallic but in the case of NiCrSi the Ni-based contacts present spinpolarization at the Fermi level over 90%. Finally, we show that there are two cases of defects and atomic-swaps. The first-ones which involve the Cr(Mn) and Si atoms induce states at the edges of the gap which persists for a moderate-concentration of defects. Defects involving Ni atoms induce states localized within the gap completely destroying the half-metallicity. Based on single-impurity calculations we associate these states to the symmetry of the crystal.

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“…For our calculation we employ the Korringa-Kohn-Rostoker (KKR) method [27] as in the case of the perfect bulk [13] and interfaces [20] and we have treated the impurities as in Refs. [26,28].…”

Section: Introductionmentioning

confidence: 98%

Effect of interfacial defects on the electronic and magnetic properties of epitaxial CrAs/InAs and CrAs/CdSe half-metallic multilayers

Galanakis¹,

Lekkas²

2010

Journal of Magnetism and Magnetic Materials

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a b s t r a c tWe present an extended study of single impurity atoms at the interface between the half-metallic ferromagnetic zinc-blende CrAs compound and the zinc-blende binary InAs and CdSe semiconductors in the form of very thin multilayers. Contrary to the case of impurities in the perfect bulk CrAs studied in Galanakis and Pouliasis [J. Magn. Magn. Mater. 321 (2009) 1084] defects at the interfaces do not alter in general the half-metallic character of the perfect systems. The only exception are Void impurities at Cr or In(Cd) sites which lead, due to the lower-dimensionality of the interfaces with respect to the bulk CrAs, to a shift of the p bands of the nearest neighboring As(Se) atom to higher energies and thus to the loss of the half-metallicity. But Void impurities are Schottky-type and should exhibit high formation energies and thus we expect the interfaces in the case of thin multilayers to exhibit a robust halfmetallic character.

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Lattice relaxations and hyperfine fields of heavy impurities in Fe

Cited by 32 publications

References 36 publications

Hyperfine Fields of Light Interstitial Impurities in Ni

Hyperfine Fields of Light Interstitial Impurities in Ni

Ab initio electronic and magnetic properties of half-metallic NiCrSi and NiMnSi Heusler alloys: The role of defects and interfaces

Effect of interfacial defects on the electronic and magnetic properties of epitaxial CrAs/InAs and CrAs/CdSe half-metallic multilayers

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