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Title: Structural, electronic and magnetic properties of the MnGa(111)-1 × 2 and 2 × 2 reconstructions: Spin polarized first principles total energy calculations

Authors:
; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1397082
Grant/Contract Number:
FG02-06ER46317
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Applied Surface Science
Additional Journal Information:
Journal Volume: 419; Journal Issue: C; Related Information: CHORUS Timestamp: 2018-01-03 22:15:19; Journal ID: ISSN 0169-4332
Publisher:
Elsevier
Country of Publication:
Netherlands
Language:
English

Citation Formats

Garcia-Diaz, Reyes, Cocoletzi, Gregorio H., Mandru, Andrada-Oana, Wang, Kangkang, Smith, Arthur R., and Takeuchi, Noboru. Structural, electronic and magnetic properties of the MnGa(111)-1 × 2 and 2 × 2 reconstructions: Spin polarized first principles total energy calculations. Netherlands: N. p., 2017. Web. doi:10.1016/j.apsusc.2017.04.241.
Garcia-Diaz, Reyes, Cocoletzi, Gregorio H., Mandru, Andrada-Oana, Wang, Kangkang, Smith, Arthur R., & Takeuchi, Noboru. Structural, electronic and magnetic properties of the MnGa(111)-1 × 2 and 2 × 2 reconstructions: Spin polarized first principles total energy calculations. Netherlands. doi:10.1016/j.apsusc.2017.04.241.
Garcia-Diaz, Reyes, Cocoletzi, Gregorio H., Mandru, Andrada-Oana, Wang, Kangkang, Smith, Arthur R., and Takeuchi, Noboru. 2017. "Structural, electronic and magnetic properties of the MnGa(111)-1 × 2 and 2 × 2 reconstructions: Spin polarized first principles total energy calculations". Netherlands. doi:10.1016/j.apsusc.2017.04.241.
@article{osti_1397082,
title = {Structural, electronic and magnetic properties of the MnGa(111)-1 × 2 and 2 × 2 reconstructions: Spin polarized first principles total energy calculations},
author = {Garcia-Diaz, Reyes and Cocoletzi, Gregorio H. and Mandru, Andrada-Oana and Wang, Kangkang and Smith, Arthur R. and Takeuchi, Noboru},
abstractNote = {},
doi = {10.1016/j.apsusc.2017.04.241},
journal = {Applied Surface Science},
number = C,
volume = 419,
place = {Netherlands},
year = 2017,
month =
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on May 14, 2018
Publisher's Accepted Manuscript

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  • Intermetallic compounds which are ductile at high temperatures are of great technological interest; however, purely experimental searches for improved intermetallic materials are time consuming and expensive. Theoretical studies can shorten the experimental search by focusing on compounds with the desired properties. While current {ital ab} {ital initio} density-functional calculations cannot adequately determine material properties at high temperature, it is possible to compute the static-lattice equation of state and elastic moduli of ordered binary compounds. Known correlations between equilibrium properties and high-temperature properties such as the melting temperature can then be used to point the way for experiments. We demonstrate themore » power of this approach by applying the linear augmented-plane-wave method to the calculation of the equation of state and all of the zero-pressure elastic moduli for SbY in the {ital B}1 (NaCl) phase, CoAl and RuZr in the {ital B}2 (CsCl) phase, and NbIr in the {ital L}1{sub 0} (Au-Cu I) phase. The calculated equilibrium lattice constants are all within 2% of the experimentally determined values. The only experimentally known elastic moduli in these systems are the bulk and shear moduli for polycrystalline SbY, CoAl, and NbIr. The predicted bulk moduli are with 7% of experiment. Theory enables us to place limits on the experimental polycrystalline shear modulus. The experimental shear moduli of SbY and CoAl are within our theoretical bounds, but the experimental shear modulus of NbIr is 35% smaller than our lower bound. We stress that in the case of CoAl our calculations provided a prediction for the bulk and shear moduli that were subsequently confirmed by the experiments of Fleischer. We also discuss the band structures and electronic density of states for these materials.« less
  • This work reports on the electronic, magnetic, and structural properties of the binary intermetallic compounds Mn{sub 3-x}Ga. The tetragonal DO{sub 22} phase of the Mn{sub 3-x}Ga series, with x varying from 0 to 1.0 in steps of x=0.1, was successfully synthesized and investigated. It was found that all these materials are hard magnetic, with energy products ranging from 10.1 kJ m{sup -3} for low Mn content (x{yields}1) to 61.6 kJ m{sup -3} for high Mn content (x{yields}0). With decreasing Mn content, the average saturation magnetization per atom increases from 0.26{mu}{sub B} for Mn{sub 3}Ga to 0.47{mu}{sub B} for Mn{sub 2}Ga.more » The increase in the saturation magnetization as the Mn content is reduced indicates a ferrimagnetic order with partially compensating moments of the two different Mn atoms on the two crystallographically different sites of the DO{sub 22} structure. This type of magnetic order is supported by ab initio calculations of the electronic structure that predict a nearly half-metallic ferrimagnet with the highest spin polarization of 88% at the Fermi energy for Mn{sub 3}Ga. The Curie temperature of the compounds is restricted to approximately 770 K because of a structural phase transition to the hexagonal DO{sub 19} phase. Thermal irreversibilities between zero-field-cooled and field-cooled measurements suggest that the Mn{sub 3-x}Ga series belongs to the class of magnetically frustrated ferrimagnets. The most pronounced magnetic anomaly is found for Mn{sub 3}Ga.« less
  • The electronic, elastic and dynamical properties of the quaternary alloy FeNiMnAl have been investigated using a pseudopotential plane wave method within the generalized gradient approximation (GGA). We determined the lattice parameters and the bulk modulus B. In addition, the elastic properties such as elastic constans (C{sub 11}, C{sub 12} and C{sub 44}), the shear modulus G, the young modulus E, the poisson's ratio σ and the B/G ratio are also given. The FeNiMnAl Heusler alloy exhibit a ferromagnetic half-metallic behavior with the total magnetic moment of 4.02 μ{sub B}. The phonon dispersion of FeNiMnAl has been performed using the densitymore » functional theory and the direct method with 2×2×2 supercell.« less
  • The band structures of the ferromagnetic compounds FeB, Fe{sub 2}B, and Fe{sub 3}B were calculated using a spin-polarized version of the first-principles self-consistent orthogonalized linear-combination-of-atomic-orbitals method. Results on the band structure, density of states (DOS), and site-, orbital-, and spin-decomposed partial DOS are presented. Mulliken population analysis indicates B to be an electron accepter in these compounds due to the low-lying levels of the B 2{ital s} and B 2{ital p} states relative to the Fermi level. It is also shown that the moment on B is slightly polarized opposite to the Fe moments. The magnetic structure and bonding inmore » these three compounds are further revealed by the presentation of contour maps for the charge density and the spin density. Our calculation shows an average spin magnetic moment of 1.26, 1.95, and 1.94{mu}{sub {ital B}} per Fe site and {minus}0.10, {minus}0.23, and {minus}0.29{mu}{sub {ital B}} per B site in FeB, Fe{sub 2}B, and Fe{sub 3}B, respectively. The results are in reasonable agreement with photoemission and neutron-scattering measurements. The nature of the Fe-B bond is discussed in connection with the electronic structure of Nd{sub 2}Fe{sub 14}B intermetallic compounds and that of the Fe{sub 1{minus}{ital x}}B{sub {ital x}} metallic glasses.« less
  • The Nb{sub 2}FeB{sub 2} phase (U{sub 3}Si{sub 2}-type, space group P4/mbm, no. 127) is known for almost 50 years, but until now its magnetic properties have not been investigated. While the synthesis of Nb{sub 2}OsB{sub 2} (space group P4/mnc, no. 128, a twofold superstructure of U{sub 3}Si{sub 2}-type) with distorted Nb-layers and Os{sub 2}-dumbbells was recently achieved, “Nb{sub 2}RuB{sub 2}” is still not synthesized and its crystal structure is yet to be revealed. Our first principles density functional theory (DFT) calculations have confirmed not only the experimental structures of Nb{sub 2}FeB{sub 2} and Nb{sub 2}OsB{sub 2}, but also predict “Nb{submore » 2}RuB{sub 2}” to crystalize with the Nb{sub 2}OsB{sub 2} structure type. According to chemical bonding analysis, the homoatomic B–B interactions are optimized and very strong, but relatively strong heteroatomic M–B, B–Nb and M–Nb bonds (M=Fe, Ru, Os) are also found. These interactions, which together build a three-dimensional network, are mainly responsible for the structural stability of these ternary borides. The density-of-states at the Fermi level predicts metallic behavior, as expected, from metal-rich borides. Analysis of possible magnetic structures concluded preferred antiferromagnetic ordering for Nb{sub 2}FeB{sub 2}, originating from ferromagnetic interactions within iron chains and antiferromagnetic exchange interactions between them. -- Graphical abstract: Nb{sub 2}FeB{sub 2} (U{sub 3}Si{sub 2} structure type, space group P4/mbm, no. 127) is predicted to order antiferromagnetically, due to the presence of iron chains which show ferromagnetic interactions in the chains and antiferromagnetic interactions between them. “Nb{sub 2}RuB{sub 2}” is predicted to crystallize with the recently discovered Nb{sub 2}OsB{sub 2} twofold superstructure (space group P4/mnc, no. 128) of U{sub 3}Si{sub 2} structure type. The building of ruthenium dumbbells instead of chains along [001] is found to be responsible for the stabilization of this superstructure. Highlights: • Nb{sub 2}FeB{sub 2} is predicted to order antiferromagnetically. • Ferromagnetic interactions found in iron chains and antiferromagnetic ones between them. • Unknown “Nb{sub 2}RuB{sub 2}” predicted to crystallize with a twofold U{sub 3}Si{sub 2} superstructure. • Puckering of Nb-layer and Ru-dumbbell formation responsible for superstructure occurrence.« less