Experimental and theoretical study of the electronic structures of Ni3Al, Ni3Ga, Ni3In, and NiGa

Hsu, L. S.; Wang, Yin-Kuo; Guo, Guang‐Yu

doi:10.1063/1.1491018

Cited by 28 publications

(30 citation statements)

References 42 publications

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“…Our calculated equilibrium lattice parameter a is in excellent agreement with the experimental data and it is quite equal to the experimental value in Ref. [15] from GGA-PBEsol calculation. …”

Section: Structural Propertiessupporting

confidence: 79%

High Pressure Behaviour of Elastic and Mechanical Properties of NiGa Intermetallic Compound

2016

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We have employed the density functional theory plane-wave pseudopotential method with local density approximation and generalized gradient approximation to investigate the structural, elastic and mechanical properties of the intermetallic compound NiGa. The calculated equilibrium lattice constant and bulk modulus are in good agreement with the experimental and other calculated values. According to our best knowledge, from the elastic constants, the bulk modulus B, anisotropy factor A, shear modulus G, the Young modulus E and the Poisson ratio σ for NiGa compound are obtained for the first time. By comparison, our results for the elastic constants Cij, bulk modulus B, shear modulus G and the Young modulus E are as good as those of NiAl compound. The dependences of the elastic and mechanical parameters of NiGa compound on pressure were also investigated. It was found that the cubic NiGa compound is mechanically stable under pressure according to the elastic stability criteria up to 13 GPa, and it is not elastically isotropic. By analyzing the ratio (B/G), it was concluded that NiGa compound is ductile in nature.

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Section: Structural Propertiessupporting

confidence: 79%

High Pressure Behaviour of Elastic and Mechanical Properties of NiGa Intermetallic Compound

2016

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“…Since fluctuations are generically antagonistic to ordering, the result is that magnetic moments and magnetic energies of weak itinerant ferromagnets near critical points are overestimated in the LDA, as opposed to LDA's failure to describe MottHubbard insulators where the LDA underestimates the tendency to magnetism. Recent examples include Sc 3 In [6], Ni 3 Al [13], NaCo 2 O 4 [8], and ZrZn 2 [9]. Similarly, susceptibilities of paramagnets near critical points are underestimated.…”

mentioning

confidence: 99%

“…Furthermore, there is an overlap region where the LDA predicts ferromagnetism for paramagnetic materials. This interesting class includes FeAl [11,12], Ni 3 Ga [13], and Sr 3 Ru 2 O 7 [7] (as mentioned, this latter material shows a metamagnetic quantum critical point). The basic theoretical difficulty in correcting the LDA for these materials is that there is some unknown and possibly strongly material dependent cross-over in energy (and possibly non-trivially in momentum) separating quantum critical fluctuations, not included in the LDA, from the dynamical fluctuations that are included in the LDA.…”

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confidence: 99%

Magnetism, critical fluctuations, and susceptibility renormalization in Pd

2004

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Some of the most popular ways to treat quantum critical materials, that is, materials close to a magnetic instability, are based on the Landau functional. The central quantity of such approaches is the average magnitude of spin fluctuations, which is very difficult to measure experimentally or compute directly from the first principles. We calculate the parameters of the Landau functional for Pd and use these to connect the critical fluctuations beyond the local-density approximation and the band structure.The physics and materials science of weak itinerant ferromagnetic metals and highly renormalized paramagnets near magnetic instabilities has attracted renewed theoretical interest. This is a result of recent discoveries of materials with highly non-conventional metallic properties, especially, non-Fermi liquid scalings, metamagnetic behavior, and unconventional superconductivity, in several cases co-existing with ferromagnetism. Discoveries in the last three years alone include the co-existing ferromagnetism and superconductivity of Unfortunately, although model theories have been put forth, there is still not an established material specific (first principles) theoretical understanding of these phenomena. One difficulty is the usual starting point for first principles theories, density functional theory (DFT) as implemented in the local density approximation (LDA). This already includes most spin degrees of freedom, including dynamical fluctuations, as evidenced by its formally exact description of the uniform electron gas as well as its well documented success in accurately describing a wide variety of itinerant magnetic materials. However, the electron gas, upon which most density functionals are built, is not near any critical point for densities relevant to the solid state, and furthermore the proximity to itinerant magnetism of a metal is an extremely non-local quantity, in particular depending on the electronic density of states at the Fermi level N (E F ). Therefore, the exact DFT, which by definition includes all fluctuations and describes the ground state magnetization exactly, is likely to be extremely nonlocal and probably nonanalytical for the materilas near a quantum critical point.On the other hand, the LDA, while providing a good description of most itinerant ferromagnets that are not near critical points, fails to include the soft critical fluctuations in the materials of interest here. Since fluctuations are generically antagonistic to ordering, the result is that magnetic moments and magnetic energies of weak itinerant ferromagnets near critical points are overestimated in the LDA, as opposed to LDA's failure to describe (as mentioned, this latter material shows a metamagnetic quantum critical point). The basic theoretical difficulty in correcting the LDA for these materials is that there is some unknown and possibly strongly material dependent cross-over in energy (and possibly non-trivially in momentum) separating quantum critical fluctuations, not included in the LDA, from the dynamical f...

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“…In particular, we can rule out NiGa and Ni 3 Ga, phases expected to form at our anneal temperatures, 15 since they are not magnetic or paramagnetic. 29,30 One key difference between Ni on sapphire and on GaN is the surface energy density which, along with the Ni-GaN interface energy, determines the wetting behavior of Ni. The surface energy densities for Ni and sapphire are 2.011 J/m 2 to 2.426 J/m 2 13 and 0.905 J/m 2 , 14 respectively.…”

Section: Resultsmentioning

confidence: 99%

Growth of GaN Nanowires on Epitaxial GaN

Aurongzeb

Song

Kipshidze

et al. 2008

Journal of Elec Materi

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We report experiments on the formation of GaN nanowires on epitaxial GaN using thin layers of Ni. GaN covered with Ni shows roughening that is strongly dependent on the thickness of the Ni layer and the annealing conditions. With the initial Ni thickness of 0.8 nm we observe formation of Ni-filled antidots. These act as nucleation sites in the growth of GaN nanowires, allowing for the preparation of nanowires with an average diameter as small as 30 nm. Dense and well-oriented nanowires are formed by pulsed metallorganic chemical vapor deposition at 750°C. The size of the Ni features determines the diameter of the GaN nanowires, resulting in good control over the formation process.

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Experimental and theoretical study of the electronic structures of Ni3Al, Ni3Ga, Ni3In, and NiGa

Cited by 28 publications

References 42 publications

High Pressure Behaviour of Elastic and Mechanical Properties of NiGa Intermetallic Compound

High Pressure Behaviour of Elastic and Mechanical Properties of NiGa Intermetallic Compound

Magnetism, critical fluctuations, and susceptibility renormalization in Pd

Growth of GaN Nanowires on Epitaxial GaN

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