Minor Bands Research Articles

Harmonic generation predominantly from a single spin channel in a half metal

Harmonic generation in atoms and molecules has reshaped our understanding of ultrafast phenomena beyond the traditional nonlinear optics and has launched attosecond physics. Harmonics from solids represent a new frontier, where both majority and minority spin channels contribute to the harmonics. This is true even in a ferromagnet whose electronic states are equally available to optical excitation. Here, we demonstrate that harmonics can be generated mostly from a single spin channel in half-metallic chromium dioxide. An energy gap in the minority channel greatly reduces the harmonic generation, so the harmonics predominantly emit from the majority channel, with a small contribution from the minority channel. However, this is only possible when the incident photon energy is well below the energy gap in the minority channel, so all the transitions in the minority channel are virtual. The onset of the photon energy is determined by the transition energy between the dipole-allowed transition between the $\mathrm{O}\text{\ensuremath{-}}2p$ and $\mathrm{Cr}\text{\ensuremath{-}}3d$ states. The harmonics mainly from a single spin channel can be detected, regardless of laser field strength, as long as the photon energy is below the minority band energy gap. This prediction should be tested experimentally.

Vibrational Hamiltonian of Naphthalene (C10H8) Using Dynamical U(2) Lie Algebras

This article is the first to demonstrate the application of dynamical U(2) Lie algebras to model a vibrational Hamiltonian of naphthalene (C10H8), a prototype polycyclic aromatic hydrocarbon molecule containing a fused pair of benzene rings, in the gas phase having considerable astrophysical interest. A vibrational Hamiltonian that preserves the D2h symmetry of naphthalene is modeled using 19 coupled one-dimensional Morse oscillators to describe the eight C-H single bonds, the eleven C-C aromatic bonds, and their dynamic interactions, making use of the Casimir and Majorana operators. Results indicate that the dynamical U(2) Lie algebraic Hamiltonian has successfully reproduced the vibrational frequencies at the 48 fundamental excitations near to the level of spectroscopic accuracy, as well as predicted their first three overtones. The observed degeneracy of the stretching, bending, and combination vibrations at the fundamental and lower overtone excitations are expected to modify the shape of the two major bands (centered at 782 cm−1 and 3065 cm−1), and several minor bands in the infrared absorption spectrum of naphthalene in the gas phase.

Neutron and XRD Single-Crystal Diffraction Study and Vibrational Properties of Whitlockite, the Natural Counterpart of Synthetic Tricalcium Phosphate

A crystal chemical investigation of a natural specimen of whitlockite, ideally Ca9Mg(PO4)6[PO3(OH)], from Palermo Mine (USA), was achieved by means of a combination of electron microprobe analysis (EMPA) in WDS mode, single-crystal neutron diffraction probe (NDP) and single-crystal X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The crystal-chemical characterization resulted in the empirical formula (Ca8.682Na0.274Sr0.045)Σ9.000(Ca0.034□0.996)Σ1.000(Mg0.533Fe2+0.342Mn2+0.062Al0.046)Σ0.983(P1.006O4)6[PO3(OH0.968F0.032)Σ1.000]. Crystal-structure refinement, in the space group R3c, converged to R1 = 7.12% using 3273 unique reflections from NDP data and to R1 = 2.43% using 2687 unique reflections from XRD data. Unit cell parameters from NDP are a = 10.357(3) Å, c = 37.095(15) Å and V = 3446(2) Å3, and from XRD, the parameters are a = 10.3685(4) Å, c = 37.1444(13) Å and V = 3458.2(3) Å3. NDP results allowed a deeper definition of the hydrogen-bond system and its relation with the structural unit [PO3(OH)]. The FTIR spectrum is very similar to that of synthetic tricalcium phosphate Ca3(PO4)2 and displays minor band shifts due to slightly different P-O bond lengths and to the presence of additional elements in the structure. A comparison between whitlockite, isotypic phases from the largest merrillite group, and its synthetic counterpart Ca3(PO4)2 is provided, based on the XRD/NDP and FTIR results.

Band structure tuning of Heusler compounds: Spin- and momentum-resolved electronic structure analysis of compounds with different band filling

Half-metallic ferromagnetic Heusler compounds represent an important class of materials for spintronic applications. We experimentally observe the dispersion of electronic bands with spin resolution in three representative Heusler compounds (${\mathrm{Co}}_{2}\mathrm{MnGa}, {\mathrm{Co}}_{2}\mathrm{MnSi}$, and ${\mathrm{Co}}_{2}{\mathrm{Fe}}_{0.4}{\mathrm{Mn}}_{0.6}\mathrm{Si}$). Bulk-sensitive measurements at very low photon energy are complemented by spin-integrated hard x-ray angular resolved photoemission spectroscopy. The dispersion of majority and minority electrons allows us to link exchange splitting and band filling to the number of valence electrons ${N}_{v}$. Photoexcitation at $h\ensuremath{\nu}=6.05\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$ gives access to the spin-polarization texture $\mathbit{P}({E}_{B},{k}_{x},{k}_{y})$ of the bulk bands covering a $({k}_{x},{k}_{y})$ range of 60% of the Brillouin zone. We find that ${\mathrm{Co}}_{2}\mathrm{MnSi}$ and ${\mathrm{Co}}_{2}{\mathrm{Fe}}_{0.4}{\mathrm{Mn}}_{0.6}\mathrm{Si}$ exhibit minority band gaps of 0.5 and 0.35 eV, i.e., decreasing band gap with increasing ${N}_{\mathrm{V}}$ in contrast to the rigid-band expectation. For ${\mathrm{Co}}_{2}\mathrm{MnGa}$, the minority valence state maximum lies at approx. 0.2 eV above ${E}_{\mathrm{F}}$.

Microstructure and Mechanical Properties of 6061 Al/AZ31 Mg Joints Friction Stir Lap Welded by a Tool with Variable-Pitch Thread Pin

Sheets of 6061-T6 aluminum alloy (thickness = 3 mm) and AZ31 magnesium alloy were friction stir lap welded by a tool with a variable-pitch thread pin (coarse-threaded in the upper part and fine-threaded in the lower part). For the same rotation speed and welding speed, the heat input was higher in joints with an upper Al alloy (Configuration Al-Mg) than in those with an upper Mg alloy (Configuration Mg-Al). In Configuration Al-Mg, these two dissimilar metals were poorly mixed and Al dominated the stirred zone (SZ). Many intermetallic compounds (IMCs) of Al3Mg2 formed inside the SZ. In Configuration Mg-Al, Mg alloy bands, flocculent Al12Mg17 bands, and minor Al alloy bands intersected in the SZ, forming a complex onion-ring structure. Moreover, a complex mechanical interlocking structure developed at the bottom interface of the SZ. The maximum tensile shear strengths of the Al-Mg and Mg-Al lap configurations were 160.3 and 217 N/mm, respectively, at 700 rpm. The higher tensile shear strength of the Mg-Al configuration primarily represented less IMCs and complex mechanical interlocking structures in the SZ.

Crosstalk between vrille transcripts, proteins, and regulatory elements controlling circadian rhythms and development in Drosophila.

SummaryThe vrille (vri) gene encodes a transcriptional repressor required for Drosophila development as well as circadian behavior in adults. Alternate first exons produce vri transcripts predicted to produce a short VRI isoform during development and long VRI in adults. A vri mutant (vriΔ679) lacking long VRI transcripts is viable, confirming that short VRI is sufficient for developmental functions, yet behavioral rhythms in vriΔ679 flies persist, showing that short VRI is sufficient for clock output. E-box regulatory elements that drive rhythmic long VRI transcript expression are required for developmental expression of short VRI transcripts. Surprisingly, long VRI transcripts primarily produce short VRI in adults, apparently due to a poor Kozak sequence context, demonstrating that short VRI drives circadian behavior. Thus, E-box-driven long VRI transcripts primarily control circadian rhythms via short VRI, whereas the same E-boxes drive short VRI transcripts that control developmental functions using short VRI.

Weak spectral features on (101995) Bennu from the OSIRIS-REx Visible and InfraRed Spectrometer

Context. The NASA Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission has obtained thousands of spectra of asteroid (101955) Bennu with the OSIRIS-REx Visible and InfraRed Spectrometer. Aims. We present a spectral search for minor absorption bands and determine compositional variations on the surface of Bennu. Methods. Reflectance spectra with low and high spatial resolutions were analyzed for evidence of weak absorption bands. Spectra were also divided by a global average spectrum to isolate unique spectral features, and variations in the strongest band depths were mapped on a surface shape model. The global visible to near-IR spectrum of Bennu shows evidence of several weak absorption bands with depths of a few percent. Results. Several observed bands are consistent with phyllosilicates, and their distribution correlates with the stronger 2.74-μm hydration band. A 0.55-μm band is consistent with iron oxides and is deepest in the spectrally reddest areas on Bennu. The presence of hydrated phyllosilicates and iron oxides indicates substantial aqueous alteration in Bennu’s past. Conclusions. Bennu’s spectra are not identical to a limited set of carbonaceous chondrite spectra, possibly due to compositional properties and spatial scale differences; however, returned samples should contain a mixture of common chondrite materials.

Investigating structure, magneto-electronic, and thermoelectric properties of the new d0 quaternary Heusler compounds RbCaCZ (Z = P, As, Sb) from first principle calculations

The ab initio calculations based on the density functional theory (DFT) using the self-consistent full potential linearized augmented plane wave (FPLAPW) method were performed to explore the electronic structures, magnetic and thermoelectric properties of quaternary alloys RbCaCZ (Z = P, As, Sb) with quaternary Heusler structure. Results showed that FM-Y3 is the most favorable atomic arrangement. All the compounds are found to be half-metallic ferromagnetic materials with an integer magnetic moment of 2.00 μB, which predominantly derives from the strong spin polarization of p channels of C hybridized with Z elements. The predicted minority (half-metallic) band gaps were found to be 1.86 (0.87), 1.72 (0.78), and 1.78 (0.71) eV for Z = P, As, and Sb, respectively. Thermoelectric properties of the RbCaCZ (Z = P, As, Sb) materials are additionally computed over an extensive variety of temperature and it is discovered that all compounds demonstrates higher figure of merit. The half-metallic structures of these compounds with large band gaps and adequate Seebeck coefficients mean that they are suitable for use in spintronic and thermoelectric device applications.

NEDD4-like ubiquitin ligase 2 protein (NEDL2) in porcine spermatozoa, oocytes, and preimplantation embryos and its role in oocyte fertilization†.

The ubiquitin-proteasome system plays diverse regulatory and homeostatic roles in mammalian reproduction. Ubiquitin ligases are the substrate-specific mediators of ubiquitin-binding to its substrate proteins. The NEDD4-like ubiquitin ligase 2 (aliases NEDL2, HECW2) is a HECT-type ubiquitin ligase that contains one N-terminal HECW ubiquitin ligase domain, one C-terminal HECT ubiquitin ligase domain, one C2 domain, and two WW protein-protein interaction modules. Beyond its predicted ubiquitin-ligase activity, its cellular functions are largely unknown. Current studies were designed to investigate the content and distribution of NEDL2 in porcine spermatozoa, oocytes, zygotes, and early preimplantation embryos, and in cumulus cells before and after in vitro maturation with oocytes, and fibroblast cells as positive control by western blot and immunocytochemistry, and to examine its roles during oocyte fertilization. Multiple isoforms of NEDL2 were identified by WB. One at approximately 52kDa was detected only in the germinal vesicle (GV) stage and metaphase II oocytes, and in early preimplantation embryos. Other isoforms were high mass bands at 91, 136, and 155kDa, which were only detected in somatic cells. Interestingly, ejaculated spermatozoa prominently displayed the same 52kDa band as oocytes; they also had two minor bands of 74 and 129kDa, which were not detected in somatic cells or oocytes. By immunofluorescence, NEDL2 showed a diffused cytoplasmic localization in all cell types and accumulated in distinct foci in the germinal vesicles (GVs) of immature oocytes, in maternal and paternal pronuclei of zygotes and nuclei of embryo blastomeres and somatic cells. In blastocysts, the labeling intensity of NEDL2 was stronger in the inner cell mass than in trophoblast, indicating higher NEDL2 content in the ICM cells than in trophectoderm. NEDL2 abundance was 10 times higher in post-maturation oocyte-surrounding cumulus cells than that of cumulus cells before in vitro maturation with hormones, indicating that NEDL2 may have a unique role in cumulus cells after ovulation. Microinjection of anti-NEDL2 antibody into oocyte before IVF did not affect the percentage of oocytes fertilized, percentage of oocytes cleaved, or blastocyst formation. However, the anti-NEDL2 antibody decreased the number of pronuclei, accelerated the formation of nuclear precursor bodies at 6h postfertilization, inhibited sperm DNA decondensation, and resulted in more fertilized oocytes without male pronuclear formation. In summary, NEDL2 may play a key role during fertilization, especially during sperm DNA decondensation.

Heat capacity signature of frustrated trimerons in magnetite

Recently it has been proposed that the long-range electronic order formed by trimerons in magnetite should be frustrated due to the great degeneracy of arrangements linking trimerons. This result has important consequences as charge ordering from the condensed minority band electrons leads to a complex 3D antiferro orbital order pattern. Further more, the corner sharing tetrahedra structure of spinel B-sites supports frustration for antiferromagnetic alignments. Therefore frustration due to competing interactions will itself induce disorder and very likely frustration in the spin orientations. Here we present very low temperature specific heat data that show two deviations to the magnons and phonons contributions, that we analyze in terms of Schottky-type anomalies. The first one is associated with the thermal activation across both ferroelastic twin and ferromagnetic anti-phase domains. The second Schottky-type anomaly displays an inverse (1/H) field dependence which is a direct indication of the disordered glassy network with macroscopically degenerated singular ground states.

Ultramafic Rock Carbonation: Constraints From Listvenite Core BT1B, Oman Drilling Project

AbstractThe occurrence of the quartz‐carbonate alteration assemblage (listvenite) in ophiolites indicates that ultramafic rock represents an effective sink for dissolved CO2. However, the majority of earlier studies of ultramafic rock carbonation had to rely on the surface exposure of reaction textures and field relationships. Here we present the first observations on ultramafic rock alteration obtained from the 300 m deep BT1B drill hole, ICDP Oman Drilling Project, allowing for a continuous and high‐resolution investigation. Hole BT1B recovered continuous drill core intersecting surface alluvium, 200 m of altered ultramafic rock comprising mainly listvenite and minor serpentinite bands at 90 and 180 m depth, and 100 m of the underlying metamorphic sole. Textural evidence suggests that the carbonation of fully serpentinized harzburgite commenced by non‐equilibrium growth of spheroidal carbonate characterized by sectorial zoning resulting from radially oriented low‐angle boundaries. In the serpentinite, carbonate spheroids are composed of alternating magnesite cores and dolomite rims, whereas texturally similar carbonate in the listvenite is composed of Fe‐rich magnesite cores and Ca‐Fe‐rich magnesite rims. The distinct compositions and mineral inclusions indicate that the carbonation extent was controlled by fluid accessibility resulting in the simultaneous formation of limited carbonate in the serpentinite bands and complete carbonation in the listvenite parts of BT1B. The presence of euhedral magnesite overgrowing spheroidal carbonate in the listvenite suggests near‐equilibrium conditions during the final stage of carbonation. The carbonate clumped isotope thermometry constrains carbonate crystallization between 50 °C and 250 °C, implying repeated infiltration of reactive fluids during ophiolite uplift and cooling.

Twinned-serrated chip formation with minor shear bands in ultra-precision micro-cutting of bulk metallic glass

Bulk metallic glasses (BMGs) have unique properties due to their amorphous atomic structure such as excellent mechanical and thermal performances; BMGs are considered to be promising materials for many engineering applications. However, it is important to investigate the cutting mechanisms of BMG in ultra-precision micro-cutting (UPMC). This study focuses on experimental and theoretical investigations on the chip formation in UPMC of BMG. It was firstly found that twinned-serrated chips (TSCs) are generated in UPMC of BMG. The intrinsic cause is that BMG exhibits significant adiabatic effect, which was confirmed by a proposed finite element model. A series of ultra-precision micro-cutting tests have been carried out to verify the results of simulation and reveal the effect of rake angle on the cutting process of BMG. The simulation and experiment of chip formation proved that the adiabatic effect is the key factor to generate the serrated chips in the UPMC of BMG. In addition, there existed twinned shear in one cyclic of each serrated chip. The comparison between simulation and experiment under the machining condition of different tool rake angles showed that the serrated chip and cutting force are sensitive to the rake angle of tool.

Microencapsulation of Fish Oil Using Fish Protein Hydrolysate, Maltodextrin, and Gum Arabic: Effect on Structural and Oxidative Stability

ABSTRACT Microencapsulated fish oil was prepared by spray drying using fish protein hydrolysate, sodium caseinate, maltodextrin, and gum Arabic as wall material. Fish protein hydrolysate was prepared from pink perch meat, and its physical and functional properties were studied. Microencapsulates prepared with a combination of sodium caseinate, maltodextrin, and gum Arabic were kept as control. The encapsulation efficiency and oil release behavior of microencapsulates was evaluated. Surface morphology and thermal properties of microencapsulates were determined by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) analysis, respectively. Fourier-transformed infrared spectroscopy analysis indicated that the spectral pattern of microencapsulates showed a similar structural pattern with a minor band shift for both control and fish protein hydrolysate containing microencapsulates. Oxidative stability of fish oil microencapsulates indicated that the sample stored under was 4°C was more stable than microencapsulates stored under 60°C and 28 ± 2°C temperature conditions. Moreover, microencapsulates containing fish protein hydrolysate had a lower thiobarbituric acid value. Results suggest that the incorporation of fish protein hydrolysate along with other wall material could improve the oxidative stability of microcapsules during storage.

Camel hydatidosis diagnostic kit: optimization of turnip and horseradish peroxidase conjugates using glutaraldehyde method.

Echinococcosis/hydatidosis is one of the most important parasitic zoonotic diseases in the world. Cystic echinococcosis increases public health and socio-economic concern due to considerable morbidity rates that give rise to elevated economic losses both in the public health part and in the farm animal field. The enzyme linked immunosorbent assay (ELISA) is consider the more accurate tool for diagnosis of hydatidosis in camels. In the present study, affinity purified Echinococcus granulosus (E. granulosus) antigens (APA) were purified from crude hydatide E. granulosus germinal layer proteins for detection of E. granulosus antibodies in infected camels, using affinity matrix (camel IgGs coupled to CNBr-activated Sepharose). The electrophoretic profile of the APA showed that it was separated into two bands; one major band of 130kDa and one minor band at 55kDa. These antigens were used successfully as specific coating antigenic proteins in detection of echinococcosis in camel. In a trial to prepare an anti-camel IgGs peroxidase conjugate; peroxidase enzyme was purified from turnip roots (TPOD) using ammonium sulfate precipitation and affinity chromatography on phenyl Sepharose CL-4B. The purified TPOD showed a major band at 35kDa. Rabbit anti-camel IgG antibodies (AC IgGs) were prepared then purified using affinity chromatography on Protein G-Sepharose. The TPOD, and commercial HRP for comparison, enzymes were conjugated to AC IgGs using 1%, 5% and 10% glutaraldehyde. The results revealed that the HRP was much better than TPOD in conjugation with AC-IgG antibodies and the 10% glutaraldehyde concentration was the most efficient concentration with ELISA titer 1:50.

Physicochemical and functional properties of proso millet storage protein fractions

The understanding of the protein structure-function relationship is very important to the study of protein chemistry. In this research, the physicochemical, functional, and structural properties of the storage protein fractions from two defatted proso millet cultivars (Dawn and Plateau) were determined and reported. The results show that protein recovery efficiency of 53.5% and 60.1% was recorded for Dawn and Plateau, respectively. The average denaturation temperature of all fractions was about 82.1 ± 3.5 °C. Surface hydrophobicity values for Dawn fractions were 11781, 10594, 316, and 2225 for albumin, globulin, and glutelin, respectively and 3415, 2865, 353, and 456 for Plateau fractions, respectively. Most of the protein fractions showed the highest solubility at pH 9 and lowest solubilities at pH ≤ 7 with solubility range from 5.7 to 100%. Emulsifying activity index (EAI) of less than 0.25 m2/g was recorded for most fractions, while the highest emulsion stability index (ESI) recorded was about 60 min. Prolamin fractions showed three major peptide bands of 11, 14, and 24 kDa while glutelin fraction revealed only a major band of 15 kDa and several minor bands of 11, 22, 24, 78, 209 kDa. No differences in the electrophoresis pattern were observed for the fraction with or without a reducing agent.

Optical, structural and magnetic characterization of Bi2−xCrxTe3 nanocrystals in oxide glass

Chromium-doped bismuth telluride (Bi2−xCrxTe3) diluted magnetic semiconductor nanocrystals were successfully synthesized in a glass matrix by the fusion method with nominal Cr concentrations of x = 0.00, 0.05, and 0.10. Transmission electron microscopy confirmed the growth of nanocrystals with an average diameter of ~5.0 nm. Shifts in X-ray diffraction peaks with increasing x indicated substitutional inclusion of Cr ions (occupying Bi sites - CrBi) in the Bi2Te3 structure. The absorption spectra for x = 0.05 and 0.10 show two intense spin-allowed bands at ~425 and 635 nm and two minor spin-forbidden bands at ~650 and 685 nm. These bands were attributed to the Cr3+ d-d transitions, according to the crystal field theory. Finally, electron paramagnetic resonance spectra from the Bi2−xCrxTe3 nanocrystals displayed Cr3+ characteristics with spin 3/2 in the d3 state, thereby confirming the trivalent state of Cr ions in the Bi2Te3 structure.

Strong particle-hole asymmetry in a 200 Kelvin superconductor

The superconducting state of metals has long provided a classic example of particle-hole symmetry (PHS) at low energy. Fermionic self-energy results based on first principles theory for the electron-phonon coupling in H$_3$S presented here illustrate strong PHS-breaking dynamics arising from the underlying sharp structure in the fermionic density of states. Thus H$_3$S is not only the superconductor with the highest critical temperature $T_c$ (through 2018), but its low energy, low temperature properties deviate strongly from textbook behavior. The minor momentum and band dependence of the fermionic self-energy allows evaluation of the momentum-resolved and zone-averaged spectral densities and interacting thermal distribution function, all of which clearly illustrate strong particle-hole asymmetry.

Structural disorder and short-range order in full Heusler alloys Fe2VAl and Co2CrAl from first principles calculations

Heusler alloys are intensively studied and applied in various spintronic devices. First principles calculations of their electronic structure allow to predict promising compounds with high spin polarization. However the theoretical predictions usually substantially deviate from experimental data. One of the reason is incorrect structural models used in the calculations. Heusler alloys are apt to form various disordered modifications with high concentration of antisite defects. In this paper we considered the effects of structural order and disorder on the electronic structure, stability and magnetic properties of full Heusler alloys Fe2VAl and Co2CrAl. The ordered Fe2VAl is non-magnetic narrow-gap semiconductor, the ordered Co2CrAl is a ferromagnet with metal behavior for majority spin band and narrow-gap semiconductor for minority one. When disordering Fe2VAl becomes a ferromagnetic metal. Co2CrAl loses minority band gap and its spontaneous magnetization reduces by 32%. Introduction of short range order in the disordered structure by increasing the portion of clusters specific for bcc structure further raised the magnetization in Fe2VAl and did not change it in Co2CrAl.

Spectra-Structure Correlations in Isotopomers of Ethanol (CX3CX2OX; X = H, D): Combined Near-Infrared and Anharmonic Computational Study.

The effect of isotopic substitution on near-infrared (NIR) spectra has not been studied in detail. With an exception of few major bands, it is difficult to follow the spectral changes due to complexity of NIR spectra. Recent progress in anharmonic quantum mechanical calculations allows for accurate reconstruction of NIR spectra. Taking this opportunity, we carried out a systematic study of NIR spectra of six isotopomers of ethanol (CX3CX2OX; X = H, D). Besides, we calculated the theoretical spectra of two other isotopomers (CH3CD2OD and CD3CH2OD) for which the experimental spectra are not available. The anharmonic calculations were based on generalized vibrational second-order perturbation theory (GVPT2) at DFT and MP2 levels with several basis sets. We compared the accuracy and efficiency of various computational methods. It appears that the best results were obtained with B2PLYP-GD3BJ/def2-TZVP//CPCM approach. Our simulations included the first and second overtones, as well as binary and ternary combinations bands. This way, we reliably reproduced even minor bands in the spectra of diluted samples (0.1 M in CCl4). On this basis, the effect of isotopic substitution on NIR spectra of ethanol was accurately reproduced and comprehensively explained.

Structural, electronic, elastic and mechanical properties of novel ZrMnAs half Heusler alloy from first principles

The influence of the properties of various materials researched on in literature such as the generalized Slater-Pauling behavior, half metallic property, and the effect of crystalline ordering, hydrostatic strain, thermodynamic properties, elastic behavior and more, have significant effects on the behavior of the materials hence rendering many half Heusler (HH) alloys ineffective for application in spintronics.We report the effect of Slater-Pauling behavior, half metallicity and crystalline ordering on the properties of three distinct phases of novel HH ZrMnAs (VEC = 16) alloy which are α- [As (0, 0, 0), Mn (0.5, 0.5, 0.5), Zr (0.25, 0.25, 0.25)] phase, β- [Mn (0, 0, 0), Zr (0.5, 0.5, 0.5), As (0.25, 0.25, 0.25)] phase and γ- [As (0, 0, 0), Zr (0.5, 0.5, 0.5), Mn (0.25, 0.25, 0.25)] phase. With emphasis on effect of the interaction of magnetic-rich Mn at all possible Wyckoff positions. The most stable phase in the face of the three phases checked is the γ- phase and it exhibits a stable half metallic behavior under hydrostatic pressure at lattice parameters between 10.84 a.u. and 12.04 a.u. It also has a magnetic moment of 2 μB in line with the Slater-Pauling rule for half metallic materials with a half metallic band gap of 1.6 eV. The electronic structure calculation reveals a semiconducting band gap in the majority band and a metallic behavior in the minority band of the alloy. Confirming a half metallic character in the γ- phase of the alloy hence, presenting it as a promising material for application in spintronic devices. The elastic property investigation of the alloy shows that the β- and γ- phases has a bulk to shear modulus (B/G) ratio of 4.364 and 4.518 respectively as against the critical value of 1.75 confirming they are ductile materials.