Electronic Structure of Rare-Earth Pnictides for Metallization of Semiconductors

1994 ◽  
Vol 337 ◽  
Author(s):  
A. G. Petukhov ◽  
W. R. L. Lambrecht ◽  
B. Segall
Keyword(s):  
Experimental Data ◽  
Rare Earth ◽  
Magnetic Moments ◽  
Magnetic Exchange ◽  
Cross Sectional ◽  
Electronic Band ◽  
Lattice Constants ◽  
Rocksalt Structure ◽  
Cohesive Energies ◽  
Electronic Band Structures

ABSTRACTThe results of first-principles calculations of the electronic band structures, equilibrium lattice constants, cohesive energies, bulk moduli, and magnetic moments are presented for the rare-earth pnictides with the rocksalt structure and chemical formula RX, where R = Gd, Er and X = N, P, As. Some of these materials are semimetals and are suitable for metallization of III-V semiconductors. The results for the lattice constants are in good agreement with experimental data. For ErAs, which is closely lattice-matched to GaAs, the calculated magnetic exchange splittings, electron and hole concentrations, Fermi surface cross-sectional areas and cyclotron masses are found to be in satisfactory agreement with the available experimental data.

Ab initio investigations of structural and electronic properties of AlSc3

2014 ◽  
Vol 03 (04) ◽  
pp. 1450019 ◽  
Author(s):  
K. L. Galav ◽  
K. B. Joshi
Keyword(s):  
Experimental Data ◽  
Electronic Properties ◽  
Density Functional ◽  
Structural Parameters ◽  
Electronic Band ◽  
Functional Theory ◽  
Lattice Constants ◽  
Structural And Electronic Properties ◽  
Murnaghan Equation ◽  
Electronic Band Structures

In this paper, structural and electronic properties of L12 and D019- AlSc 3 are presented. Calculations are performed applying crystalline orbital program within the framework of density functional theory. The exchange and correlation are treated following the Perdew–Becke–Ernzerhof ansatz. Other Al – Sc intermetallic compounds and polymorphs of Al 3 Sc , Al 2 Sc and AlSc are also investigated. The total energy calculations are coupled with the Murnaghan equation of state to determine lattice constants and bulk moduli. The data for D019- AlSc 3 are provided while deduced structural parameters for other materials are compared with the available results. Current results are reasonably in agreement with the experimental data and other reported calculations. Electronic band structures of a few Al – Sc compounds are studied with a view to examine effect of Al concentration on the formation of bands and bonds in the Al – Sc system.

Electronic Structure of Wide-Band-Gap Chalcopyrites

1992 ◽  
Vol 281 ◽  
Author(s):  
A. Petukhov ◽  
W. R. L. Lambrecht ◽  
B. Segall
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Structural Parameters ◽  
Wide Band ◽  
Orbital Method ◽  
Wide Band Gap ◽  
Electronic Band ◽  
Lattice Constants ◽  
Cohesive Energies ◽  
Electronic Band Structures

ABSTRACTElectronic band structures, equilibrium lattice constants and structural parameters, cohesive energies, and bulk moduli calculated by means of the linear-muffin-tin orbital method are presented for BeSiN2, MgSiN2 and MgSiP2 chalcopyrites. The relationships of these compounds to the “parent” III-V compounds are clarified.

scholarly journals Theoretical Investigations of Structural Phase Transitions and Magnetic, Electronic and Thermal Properties of DyNi: Under High Pressures and Temperatures

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Pooja Rana ◽  
U. P. Verma
Keyword(s):  
Thermal Properties ◽  
Rare Earth ◽  
Bulk Modulus ◽  
Density Functional ◽  
High Pressures ◽  
Magnetic Moments ◽  
Structural Phase ◽  
Rare Earth Ions ◽  
Full Potential ◽  
Electronic Band

Present work is influenced by the requirement of investigation of rare earth intermetallics due to the nonavailability of theoretical details and least information from experimental results. An attempt has been made to analyse the structural, electronic, magnetic and thermal properties of DyNi using full potential linear augmented plane wave method based on density functional theory. DyNi differs from other members of lanthanides nickelates as in ground state it crystallizes in FeB phase rather than orthorhombic CrB structure. The equilibrium lattice constant, bulk modulus, and pressure derivative of bulk modulus are presented in four polymorphs (FeB, CrB, CsCl and NaCl) of DyNi. At equilibrium the cell volume of DyNi for FeB structure has been calculated as 1098.16 Bohr3 which is comparable well with the experimental value 1074.75 Bohr3. The electronic band structure has been presented for FeB phase. The results for thermal properties, namely, thermal expansion coefficient, Gruneisen parameter, specific heat and Debye temperature at higher pressure and temperatures have been reported. The magnetic moments at equilibrium lattice constants have also been tabulated as the rare earth ions associated with large magnetic moments increase their utility in industrial field for the fabrication of electronic devices due to their magnetocaloric effect used in magnetic refrigeration.

Comparatively Low Temperature Synthesis, Characterization and Some Physical Studies on Transition Metal Vanadates

2021 ◽  
Vol 13 (2) ◽  
pp. 571-578
Author(s):  
T. Vaz ◽  
A. V. Salker
Keyword(s):  
Transition Metal ◽  
Magnetic Moments ◽  
Band Gap Energy ◽  
Electronic Band ◽  
Photo Degradation ◽  
Triclinic Structure ◽  
Pure Transition ◽  
Co Precipitation ◽  
Electronic Band Structures ◽  
Bonding Characteristics

Pure transition metal vanadates NiV2O6 and CuV2O6 were successfully prepared via co-precipitation technique as low as at 600 °C. The crystal structure and their phase formation were confirmed by X-ray powdered diffraction. Both the compounds were identified to have a single-phase triclinic structure. The bonding characteristics were studied by FTIR spectroscopy. The temperature dependence of electrical resistivity of these vanadates shows a typical semiconducting nature of NiV2O6 and CuV2O6, consistent with their electronic band structures. The calculated band gap energy values of NiV2O6 and CuV2O6 were found to be 2.42 and 2.0 eV respectively, employing a DRS UV-Visible spectrophotometer. Magnetic susceptibility measurements and calculated Magnetic moments confirm their paramagnetic nature. The photocatalytic efficiency was investigated by photo-degradation of methylene blue (MB) solutions employing solar light and found to be promising photocatalysts.

Alkali chalcogenido ortho manganates(II) A6MnQ4 (A=Rb, Cs; Q=S, Se, Te)

2018 ◽  
Vol 73 (11) ◽  
pp. 837-848 ◽  
Author(s):  
Michael Langenmaier ◽  
Tobias Rackl ◽  
Dirk Johrendt ◽  
Caroline Röhr
Keyword(s):  
Magnetic Measurements ◽  
Magnetic Moments ◽  
Electronic Band ◽  
Chiral Structures ◽  
Pure Phase ◽  
Maximum Temperatures ◽  
Alkali Elements ◽  
Electronic Band Structures ◽  
Bonding Characteristics ◽  
Tetrahedral Voids

AbstractThe six isotypic alkali ortho chalcogenido manganates A6[MnIIQ4] (A=Rb, Cs; Q=S, Se, Te) were synthesized – in most cases in pure phase – from stoichiometric mixtures of the manganese monochalcogenides MnQ, the elemental chalcogens and Rb2S/Cs2S2 (sulfido salts) or the pure alkali elements (selenido and tellurido salts) as alkali sources at maximum temperatures between 650 and 800°C. Their hexagonal crystal structures were refined by means of X-ray single crystal data (space group P63mc, Na6ZnO4-type structure, Z=2; A/Q: Rb/S: a=1019.34(2), c=792.560(10) pm, R1=0.0166; Rb/Se: a=1055.74(2), c=821.14(2) pm, R1=0.0275; Rb/Te: a=1126.68(2), c=860.54(2) pm, R1=0.0152; Cs/S: a=1056.68(2), c=831.22(2) pm, R1=0.0168; Cs/Se: a=1096.04(3), c=858.13(2) pm, R1=0.0194; and Cs/Te: a=1167.72(3), c=896.95(2) pm, R1=0.0140). The chiral structures contain isolated C3 symmetric, but very close to ideal tetrahedral, ortho manganate(II) anions [MnIIQ4]6− with Mn–Q distances of 248.7–250.7 (Q=S), 260.7–263.0 (Q=Se) and 280.0–282.4 pm (Q=Te). The chalcogenide ions form a hexagonal closed packing with slightly puckered 36 nets, in which the A(2) cations occupy 3/4 of the octahedral interstices, whereas Mn takes 1/8 and A(1) 3/8 of the tetrahedral voids. Magnetic measurements on the three Cs compounds showed Curie-Weiss behavior down to a temperature of 1.9 K, with magnetic moments significantly reduced with respect to the expected spin-only value of a d5 ion. The electronic band structures of the four salts (Na/Rb)6Mn(S/Te)4, which were calculated within the GGA+U approach, allow a comparison of the chemical bonding characteristics and the magnetic properties within the alkali cation and the chalcogenido ligand series.

THE ELECTRONIC BAND STRUCTURES FOR AN ANTIFERROMAGNETIC STATE OF Cu2Sb-TYPE INTERMETALLIC COMPOUND Cr2As

1993 ◽  
Vol 07 (01n03) ◽  
pp. 770-773 ◽  
Author(s):  
M. SHIRAI ◽  
T. KAWAMOTO ◽  
K. MOTIZUKI
Keyword(s):  
Intermetallic Compound ◽  
Electronic Band Structure ◽  
Magnetic Moments ◽  
Partial Density ◽  
Energy Splitting ◽  
Antiferromagnetic State ◽  
Good Correspondence ◽  
Electronic Band ◽  
Linearized Augmented Plane Wave ◽  
Electronic Band Structures

Electronic band structure calculations are carried out for the antiferromagnetic state of an intermetallic compound Cr2As, having the Cu2Sb-type crystal structure, by using a self-consistent linearized augmented-plane-wave (LAPW) method. The partial density of states (DOS) for Cr (II) 3d states shows a small energy splitting (about 1 eV) between the spin-up and spin-down bands, while that for Cr (I) 3d states hardly shows. The magnetic moments at Cr (I) and Cr (II) sites are evaluated to be 0.33μB and 1.37µB per atom, respectively. These values agree well with the observed values. The calculated DOS shows good correspondence with photoemission and inverse photoemission spectra measured recently.

Structural, electronic, elastic, thermodynamic and phonon properties of LaX (X = Cd, Hg and Zn) compounds in the B2 phase

2016 ◽  
Vol 30 (24) ◽  
pp. 1650169 ◽  
Author(s):  
Osman Örnek ◽  
Nihat Arıkan
Keyword(s):  
Density Functional ◽  
Phonon Dispersion ◽  
Band Structures ◽  
Pressure Derivative ◽  
Electronic Band ◽  
Lattice Constants ◽  
Density Functional Perturbation Theory ◽  
Densities Of States ◽  
Electronic Band Structures ◽  
Phonon Properties

The ab initio computations have been performed to examine the structural, elastic, electronic and phonon properties of cubic [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] compounds in the [Formula: see text] phase. The optimized lattice constants, bulk modulus, and its pressure derivative and elastic constants are evaluated and compared with available data. Electronic band structures and total and partial densities of states (DOS) have been derived for [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] compounds. The electronic band structures show metallic character; the conductivity is mostly governed by [Formula: see text]-[Formula: see text] states for three compounds. Phonon-dispersion curves have been obtained using the first-principle linear-response approach of the density-functional perturbation theory. The specific heat capacity at a constant volume [Formula: see text] of [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] compounds are calculated and discussed.

STRUCTURAL, MAGNETIC, TRANSPORT, AND ELECTRONIC PROPERTIES OF RNi4B AND RNi4Al COMPOUNDS (R = RARE EARTH)

2007 ◽  
Vol 21 (08) ◽  
pp. 431-454 ◽  
Author(s):  
T. TOLIŃSKI
Keyword(s):  
Experimental Data ◽  
Electrical Resistivity ◽  
Rare Earth ◽  
Phase Transitions ◽  
Specific Heat ◽  
Magnetic Moments ◽  
Mixed Valence ◽  
Photoemission Spectroscopy ◽  
X Ray ◽  
Magnetic Transport

We review the results of our studies on the R Ni 4X compounds, where X = B or Al and R = Y or rare earth. Additionally, many new data are provided in the case of R Ni 4 Al . However, the magnetic, structural, electronic, and transport properties are shown in order to highlight the tendencies and the behavior as a function of the f-occupancy rather than to present the detailed experimental data. We concentrate mainly on the mixed-valence and Kondo-like behavior in the CeNi 4X and the magnetic moments and phase transitions in the ferromagnetic representatives of the R Ni 4X compounds. A variety of the experimental techniques has been used in the investigations: magnetometry, neutron and X-ray diffractometry, X-ray photoemission spectroscopy as well as electrical resistivity and the specific heat measurements.

scholarly journals Rare earth-based quaternary Heusler compoundsMCoVZ(M= Lu, Y;Z= Si, Ge) with tunable band characteristics for potential spintronic applications

IUCrJ ◽  
2017 ◽  
Vol 4 (6) ◽  
pp. 758-768 ◽  
Author(s):  
Xiaotian Wang ◽  
Zhenxiang Cheng ◽  
Guodong Liu ◽  
Xuefang Dai ◽  
Rabah Khenata ◽  
...  
Keyword(s):  
Rare Earth ◽  
Magnetic Semiconductors ◽  
Magnetic Moments ◽  
Electronic Devices ◽  
Spin Filter ◽  
Lattice Constants ◽  
Half Metals ◽  
Different Types ◽  
Points Of View ◽  
Spin Gapless Semiconductors

Magnetic Heusler compounds (MHCs) have recently attracted great attention since these types of material provide novel functionalities in spintronic and magneto-electronic devices. Among the MHCs, some compounds have been predicted to be spin-filter semiconductors [also called magnetic semiconductors (MSs)], spin-gapless semiconductors (SGSs) or half-metals (HMs). In this work, by means of first-principles calculations, it is demonstrated that rare earth-based equiatomic quaternary Heusler (EQH) compounds with the formulaMCoVZ(M= Lu, Y;Z= Si, Ge) are new spin-filter semiconductors with total magnetic moments of 3 µB. Furthermore, under uniform strain, there are physical transitions from spin-filter semiconductor (MS) → SGS → HM for EQH compounds with the formula LuCoVZ, and from HM → SGS → MS → SGS → HM for EQH compounds with the formula YCoVZ. Remarkably, for YCoVZEQH compounds there are not only diverse physical transitions, but also different types of spin-gapless feature that can be observed with changing lattice constants. The structural stability of these four EQH compounds is also examined from the points of view of formation energy, cohesive energy and mechanical behaviour. This work is likely to inspire consideration of rare earth-based EQH compounds for application in future spintronic and magneto-electronic devices.

Structural and Mechanical Properties of RT2Zn20 and RFe2-xCoxZn20(R=Y, Sm; T=Fe, Ru, Os, Co, Rh and Ir)

2011 ◽  
Vol 689 ◽  
pp. 204-210 ◽  
Author(s):  
Yi Chen ◽  
Jiang Shen
Keyword(s):  
Crystal Structure ◽  
Experimental Data ◽  
Mechanical Properties ◽  
Bulk Modulus ◽  
Elastic Constants ◽  
Interatomic Potentials ◽  
Lattice Constants ◽  
Quaternary Compounds ◽  
Cohesive Energies ◽  
Good Agreement

The phase stability, crystal structure and mechanical properties of YT2Zn20 and SmT2Zn20 (T=Fe, Ru, Os, Co, Rh and Ir) compounds have been investigated by using interatomic potentials based on the lattice inversion technique. The calculated lattice constants are in good agreement with the experimental data. The lattice constants increase and Bulk modulus decrease as the transition metal T varies from 3d to 5d. The Y-based compounds with lower energies are more stable than the Sm analogs. Also, the Bulk modulus of YT2Zn20 series are larger than SmT2Zn20 series. Moreover, the mechanical properties of the quaternary compounds YFe2-xCoxZn20 and SmFe2-xCoxZn20­, such as the elastic constants and bulk modulus, have been calculated in this work. The substitution of Co atoms would decrease the cohesive energies and increase the bulk modulus of materials.

Sign in / Sign up

Export Citation Format

Share Document