Z. Szotek - Academia.edu (original) (raw)
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Papers by Z. Szotek
Physical review letters, Jan 13, 2015
We explain a profound complexity of magnetic interactions of some technologically relevant gadoli... more We explain a profound complexity of magnetic interactions of some technologically relevant gadolinium intermetallics using an ab initio electronic structure theory which includes disordered local moments and strong f-electron correlations. The theory correctly finds GdZn and GdCd to be simple ferromagnets and predicts a remarkably large increase of Curie temperature with a pressure of +1.5 K kbar^{-1} for GdCd confirmed by our experimental measurements of +1.6 K kbar^{-1}. Moreover, we find the origin of a ferromagnetic-antiferromagnetic competition in GdMg manifested by noncollinear, canted magnetic order at low temperatures. Replacing 35% of the Mg atoms with Zn removes this transition, in excellent agreement with long-standing experimental data.
ABSTRACT We present the results of a real space approach to calculating the magneto-crystalline a... more ABSTRACT We present the results of a real space approach to calculating the magneto-crystalline anisotropy energy in metals and alloys. The calculations are based on a fully relativistic and spin polarized extension of the locally selfconsistent multiple scattering (LSMS) method(Yang Wang et al. Phys. Rev. Letters 75), 2867,(1995). Advantage is taken of screened structure constants in order to render the large matrices that have to be inverted sparse. We show results for the transition metal elements Fe, Ni, and Co. Prospects for extending this method to large cell models of inhomogeneous systems such as disordered alloys and multilayers are discussed.
MRS Proceedings, 2004
We use the self-interaction corrected (SIC) local spin-density (LSD) approximation to investigate... more We use the self-interaction corrected (SIC) local spin-density (LSD) approximation to investigate the groundstate valency configuration of Mn impurities in p-type ZnO. In Zn1−xMnxO, we find the localized Mn2+ configuration to be preferred energetically. When codoping Zn1−xMnxO with N, we find that four d-states stay localized at the Mn site, while the remaining d-electron charge transfers into the hole states at the top of the valence bands. If the Mn concentration [Mn] is equal to the N concentration [N], this results in a scenario without carriers to mediate long range order. If on the other hand [N] is larger than [Mn], the N impurity band is not entirely filled, and carrier mediated ferromagnetism becomes theoretically possible.
MRS Proceedings, 2003
ABSTRACTThe electronic structures of actinide solid systems are calculated using the self-interac... more ABSTRACTThe electronic structures of actinide solid systems are calculated using the self-interaction corrected local spin density approximation. Within this scheme the 5f electron manifold is considered to consist of both localized and delo-calized states, and by varying their relative proportions the energetically most favourable (ground state) configuration can be established. Specifically, we discuss elemental Pu in its δ-phase, and the effects of adding O to PuO2.
Science, 2003
The electronic structure of PuO 2 ± x was studied using first-principles quantum mechanics, reali... more The electronic structure of PuO 2 ± x was studied using first-principles quantum mechanics, realized with the self-interaction corrected local spin density method. In the stoichiometric PuO 2 compound, Pu occurs in the Pu(IV) oxidation state, corresponding to a localized f 4 shell. If oxygen is introduced onto the octahedral interstitial site, the nearby Pu atoms turn into Pu(V) (f 3 ) by transferring electrons to the oxygen. Oxygen vacancies cause Pu(III) (f 5 ) to form by taking up electrons released by oxygen. At T = 0, the PuO 2 compound is stable with respect to free oxygen, but the delicate energy balance suggests the possible deterioration of the material during long-term storage.
Physical Review Letters, 2006
Physical Review Letters, 1999
New Journal of Physics, 2008
Journal of Physics: Condensed Matter, 2004
Physical review letters, Jan 13, 2015
We explain a profound complexity of magnetic interactions of some technologically relevant gadoli... more We explain a profound complexity of magnetic interactions of some technologically relevant gadolinium intermetallics using an ab initio electronic structure theory which includes disordered local moments and strong f-electron correlations. The theory correctly finds GdZn and GdCd to be simple ferromagnets and predicts a remarkably large increase of Curie temperature with a pressure of +1.5 K kbar^{-1} for GdCd confirmed by our experimental measurements of +1.6 K kbar^{-1}. Moreover, we find the origin of a ferromagnetic-antiferromagnetic competition in GdMg manifested by noncollinear, canted magnetic order at low temperatures. Replacing 35% of the Mg atoms with Zn removes this transition, in excellent agreement with long-standing experimental data.
ABSTRACT We present the results of a real space approach to calculating the magneto-crystalline a... more ABSTRACT We present the results of a real space approach to calculating the magneto-crystalline anisotropy energy in metals and alloys. The calculations are based on a fully relativistic and spin polarized extension of the locally selfconsistent multiple scattering (LSMS) method(Yang Wang et al. Phys. Rev. Letters 75), 2867,(1995). Advantage is taken of screened structure constants in order to render the large matrices that have to be inverted sparse. We show results for the transition metal elements Fe, Ni, and Co. Prospects for extending this method to large cell models of inhomogeneous systems such as disordered alloys and multilayers are discussed.
MRS Proceedings, 2004
We use the self-interaction corrected (SIC) local spin-density (LSD) approximation to investigate... more We use the self-interaction corrected (SIC) local spin-density (LSD) approximation to investigate the groundstate valency configuration of Mn impurities in p-type ZnO. In Zn1−xMnxO, we find the localized Mn2+ configuration to be preferred energetically. When codoping Zn1−xMnxO with N, we find that four d-states stay localized at the Mn site, while the remaining d-electron charge transfers into the hole states at the top of the valence bands. If the Mn concentration [Mn] is equal to the N concentration [N], this results in a scenario without carriers to mediate long range order. If on the other hand [N] is larger than [Mn], the N impurity band is not entirely filled, and carrier mediated ferromagnetism becomes theoretically possible.
MRS Proceedings, 2003
ABSTRACTThe electronic structures of actinide solid systems are calculated using the self-interac... more ABSTRACTThe electronic structures of actinide solid systems are calculated using the self-interaction corrected local spin density approximation. Within this scheme the 5f electron manifold is considered to consist of both localized and delo-calized states, and by varying their relative proportions the energetically most favourable (ground state) configuration can be established. Specifically, we discuss elemental Pu in its δ-phase, and the effects of adding O to PuO2.
Science, 2003
The electronic structure of PuO 2 ± x was studied using first-principles quantum mechanics, reali... more The electronic structure of PuO 2 ± x was studied using first-principles quantum mechanics, realized with the self-interaction corrected local spin density method. In the stoichiometric PuO 2 compound, Pu occurs in the Pu(IV) oxidation state, corresponding to a localized f 4 shell. If oxygen is introduced onto the octahedral interstitial site, the nearby Pu atoms turn into Pu(V) (f 3 ) by transferring electrons to the oxygen. Oxygen vacancies cause Pu(III) (f 5 ) to form by taking up electrons released by oxygen. At T = 0, the PuO 2 compound is stable with respect to free oxygen, but the delicate energy balance suggests the possible deterioration of the material during long-term storage.
Physical Review Letters, 2006
Physical Review Letters, 1999
New Journal of Physics, 2008
Journal of Physics: Condensed Matter, 2004