Band-structure calculations for Ni (original) (raw)
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Spin-polarized band-structure calculations for Ni
Physical Review B, 1979
The electronic structure of nickel as a function of the lattice constant has been studied by the self-consistent spin-polarized augmented-plane-wave method. The results confirm previous findings by Wang and Callaway regarding the different forms of the local-exchange approximation. The present calculations have incorporated the mass-velocity and Darwin relativistic effects and lead to an ordering of the energy levels at L which is consistent with photoemission measurements of Eastman et al. The computed changes in Fermi surface and magneton number with pressure were in reasonable agreement with corresponding measurements of the de Haasvan Alphen effect and magnetization 'Reference 5. Slater-Koster interpolation from 20-point mesh. 'Tetrahedron interpolation from 89-point mesh. Callaway and Wang (Ref. 4). We have assumed that there is a misprint in this paper. 'Tetrahedron interpolation from equivalent of 240-point mesh. fReference 28. &Data obtained by R. W. Stark as reported in Ref. 5. "Reference 27. 'Goy and Grimes, see Ref. 29.
Electron Momentum Density in Nickel (Ni)
Advances in Physics Theories and Applications, 2015
In this paper, Compton profile of (Ni) was Calculated by employing both the renormalized-free atom(RFA) model and free electron(FE) model setting several configurations in subset (3d-4s). The results were compared with recent data ,It shows that the RFA calculation in(3d8.8-4s1.2) gives a better agreement with experiment.The calculated data used for the first time also to compute the cohesive energy of Nickle and compared it with available data. The Band structure and Density of state of Nickel crystals(DFT-LDA) also calculated by using code Quantum wise. Keywords : Compton profile,Electron momentum density, Cohesive energy, Band structure, Density of state.
The magnetic hyperfine field at140Ce in nickel
Hyperfine Interactions, 1977
The hyperfine interaction of 14~ in nickel has been investigated by the time-differential perturbed-angular-correlation technique (TDPAC). The probe was produced by isotope separator implantation of the fission product 14~ the #-decay chain of which finally populates excited states of 14OCe" Different spin rotation spectra were observed before and after an 8 h annealing at 415~ The analysis of the spectra led to the conclusion that the Ce ions were in the diamagnetic 4 + state. The dominant contributions to the hyperfine interaction are two different magnetic hyperfine fields: [Hhfll = 385-+ 7 kOe and [Hhf21 = 276-+ 12 kOe. Hhf 1 disappears after annealing. The fraction of nuclei which observe Hhf 2 is increased by the annealing procedure from 16% to 75%. It is assumed that Hhf 1 is the hyperfine field of CeNi in an unperturbed substitutional site and Hhf 2 is attributed to Ce ions which have trapped a single vacancy.
Magnetic Compton profiles of Fe and Ni corrected by dynamical electron correlations
Physical Review B, 2012
Magnetic Compton profiles (MCPs) of Ni and Fe along [111] direction have been calculated using a combined Density Functional and many-body theory approach. At the level of the local spin density approximation the theoretical MCPs does not describe correctly the experimental results around the zero momentum transfer. In this work we demonstrate that inclusion of electronic correlations as captured by Dynamical Mean Field Theory (DMFT) improves significantly the agreement between the theoretical and the experimental MCPs. In particular, an energy decomposition of Ni MCPs gives indication of spin polarization and intrinsic nature of Ni 6 eV satellite, a genuine many-body feature.
The orbital and spin moment of the Ni 2+ ion in NiO has been calculated within the quasi-atomic approach. The orbital moment of 0.54 µB amounts at 0 K, in the magnetically-ordered state, to more than 20% of the total moment (2.53 µB). For this outcome, being in nice agreement with the recent experimental finding taking into account the spin-orbit coupling is indispensable. NiO attracts large attention of the magnetic community by more than 50 years. Despite of its simplicity (two atoms, NaCl structure, well-defined antiferromagnetism (AF) with T N of 525 K) and enormous theoretical and experimental works the consistent description of its properties, reconciling its insulating state with the unfilled 3d band is still not reached [1-4]. The aim of this short Letter is to report the calculations of the magnetic moment of NiO. We attribute this moment to the Ni 2+ ions. We have calculated the moment of the Ni 2+ ion in the NiO 6 octahedral complex, its spin and orbital parts, and the orbital moment as large as 0.54 µ B at 0 K has been revealed. The approach used can be called the quasi-atomic approach as the starting point for the description of a solid is consideration of the atomic-like structure of the constituting atoms/ions, in the present case of the Ni 2+ ions. We have treated the 8 outer electrons of the Ni 2+ ion as forming the highly-correlated electron system 3d 8. Its ground term is described by two Hund's rules yielding S=1 and L=3 i.e. the ground term 3 F [5]. Such the localized highly-correlated electron system interacts in a solid with the charge and spin surroundings. The charge surrounding has the octahedral symmetry owing to the NaCl-type of structure of NiO. Effect of small trigonal distortion experimentally observed will be discussed elsewhere. It turns out that the trigonal distortion is important for the detailed formation of the AF structure but it only slightly influences the spin and orbital moments. Our Hamiltonian for NiO consists of two terms: the single-ion-like term H d of the 3d 8 system and the d-d intersite spin-dependent term. Calculations somehow resemble those performed for rare-earth systems, see e.g. Ref. 6. For the calculations of the quasi-atomic single-ion-like Hamiltonian of the 3d 8 system we take into account the crystal-field interactions of the octahedral symmetry and the spin-orbit coupling (octahedral CEF parameter B 4 =+2 meV, the spin-orbit coupling λ=-41 meV). The single-ion states under the octahedral crystal field and the spin-orbit coupling (the NiO 6 complex) have been calculated by consideration of the Hamiltonian: H d = B 4 (O 0 4 + 5O 4 4) + λ s−o L · S (1) These calculations have revealed [7] the existence of the fine electronic structure with the charge-formed ground state containing three localized states, originating from the cubic subterm 3 A 2g , characterized by the total moment of 0 and ±2.26 µ B. For the doublet the orbital moment amounts to 0.27 µ B. It, however, fully cancels in the paramagnetic state and reveals itself only in the presence of the magnetic field, external or internal in case of the magnetically-ordered state, that polarizes two doublet states. The intersite spin-dependent interactions cause the (antiferro-)magnetic ordering. They have been considered in the mean-field approximation with the molecular-field coefficient n acting between magnetic moments m=(L+2.0023·S) µ B. The value of n in the Hamiltonian H d−d = n −m i · m i + 1 2 m 2 i (2) has been adjusted in order to reproduce the experimentally-observed Neel temperature. The fitted value of n has been found to be-200T/ µ B. It means that the Ni ion in the magnetic state experiences the molecular field of 510 T (at 0 K). The calculated value of the magnetic moment at 0 K in the magnetically-ordered state amounts to 2.53 µ B. It is built up from the spin moment of 1.99 µ B (S=0.995) and the orbital moment of 0.54 µ B. The increase of m L in comparison to the paramagnetic state is caused by the further polarization of the ground-state eigenfunction by the
The Journal of Physical Chemistry A, 2005
A dispersed fluorescence investigation of the low-lying electronic states of NiCu has allowed the observation of four out of the five states that derive from the 3d Ni 9 3d Cu 10 σ 2 manifold. Vibrational levels of the ground X 2 ∆ 5/2 state corresponding to V) 0-11 are observed and are fit to provide ω e) 275.93 (1.06 cm-1 and ω e x e) 1.44 (0.11 cm-1. The V) 0 levels of the higher lying states deriving from the 3d Ni 9 3d Cu 10 σ 2 manifold are located at 912, 1466, and 1734 cm-1 , and these states are assigned to Ω values of 3 / 2 , 1 / 2 , and 3 / 2 , respectively. The last of these assignments is based on selection rules and is unequivocal; the first two are based on a comparison to ab initio and ligand field calculations and could conceivably be in error. It is also possible that the V) 0 level of the state found at 912 cm-1 is not observed, so that T 0 for the lowest excited state actually lies near 658 cm-1. These results are modeled using a matrix Hamiltonian based on the existence of a ground manifold of states deriving from the 3d 9 configuration on nickel. This matrix Hamiltonian is also applied to the spectroscopically well-known molecules AlNi, NiH, NiCl, and NiF. The term energies of the 2 Σ + , 2 Π, and 2 ∆ states of these molecules, which all derive from a 3d 9 configuration on the nickel atom, display a clear and understandable trend as a function of the electronegativity of the ligands.
First-principles study of the neutral molecular metal Ni(tmdt)(2)
Physical Review B, 2002
The electronic structure of the molecular solid Ni(tmdt) 2 , the only well characterized neutral molecular metal to date, has been studied by means of first-principles density functional calculations. It is shown that these calculations correctly describe the metallic vs semiconducting behavior of molecular conductors of this type. The origin of the band overlap leading to the metallic character and the associated Fermi surfaces has been studied.
Comprehensive theoretical studies on the low-lying electronic states of NiF, NiCl, NiBr, and NiI
The Journal of Chemical Physics, 2006
The low-lying electronic states of the nickel monohalides, i.e., NiF, NiCl, NiBr, and NiI, are investigated by using multireference second-order perturbation theory with relativistic effects taken into account. For the energetically lowest 11 ⌳-S states and 26 ⍀ states thereinto, the potential energy curves and corresponding spectroscopic constants ͑vertical and adiabatic excitation energies, equilibrium bond lengths, vibrational frequencies, and rotational constants͒ are reported. The calculated results are grossly in very good agreement with those solid experimental data. In particular, the ground state of NiI is shown to be different from those of NiF, NiCl, and NiBr, being in line with the recent experimental observation. Detailed analyses are provided on those states that either have not been assigned or have been incorrectly assigned by previous experiments.
Solid State Communications, 2008
The hyperfine magnetic field (H h f ) in 0.2 at.% Hf-Ni alloy is measured at the 181 Ta probe using the time-differential perturbed angular correlation (TDPAC) method, in the temperature range 78-675 K. The obtained value of 8.6 (3) T at room temperature is in good agreement with the previously reported measurements for similar Hf concentrations in Ni. X-ray powder diffraction (XRPD) experiments confirmed that small atomic concentrations of Hf atoms (<1 at.%) mainly substitute on Ni lattice sites in the fcc crystal lattice without forming any intermetallic phase. In addition, ab-initio calculation using all-electron augmented plane waves plus local orbitals (APW+lo) formalism is performed and the obtained result for the hyperfine magnetic field at Ta site is in accordance with the measurement.