scholarly journals A first-principles investigation of band inversion in topologically nontrivial Na2AgX (X= As, Sb and Bi) full Heusler compounds

2021 ◽  
Vol 24 (2) ◽  
pp. 23602
Author(s):  
A. Boughena ◽  
S. Benalia ◽  
O. Cheref ◽  
N. Bettahar ◽  
D. Rached
Keyword(s):  
First Principles ◽  
Surface States ◽  
Metallic Surface ◽  
Full Potential ◽  
Topological Order ◽  
Heusler Compounds ◽  
Spin Orbital ◽  
Lmto Method ◽  
Potential Applications ◽  
Full Heusler

Topological nontrivial nature are the latest phases to be discovered in condensed matter physics with insulating bulk band gaps and topologically protected metallic surface states; they are one of the current hot topics because of their unique properties and potential applications. In this paper, we have highlighted a first-principles study of the structural stability and electronic behavior of the Na2AgX (X = As, Sb and Bi) full Heusler compounds, using the Full-Potential Linear Muffin-Tin Orbital (FP-LMTO) method. We have originated that the Hg2CuTi structure is appropriate in all studied materials. The negative values of the calculated formation energies mean that these compounds are energetically stable. The band structure is studied for the two cases relating the existence and the absence of spin-orbital couplings, where all materials are shown to be topologically non-trivial compounds. Spin orbital couplings were noticed to have no significant effect on the electronic properties such as the topological order.

scholarly journals Investigation of the structural competing and atomic ordering in Heusler compounds Fe 2 NiSi and Ni 2 FeSi under strain condition

2019 ◽  
Vol 6 (9) ◽  
pp. 191007 ◽  
Author(s):  
Tie Yang ◽  
Liyu Hao ◽  
Rabah Khenata ◽  
Xiaotian Wang
Keyword(s):  
First Principles ◽  
Magnetic Moments ◽  
Applied Strain ◽  
First Principles Calculation ◽  
Cubic Phase ◽  
Strain Condition ◽  
Heusler Compounds ◽  
Atomic Ordering ◽  
Nearest Neighbours ◽  
Full Heusler

The structural competing and atomic ordering of the full Heusler compounds Fe 2 NiSi and Ni 2 FeSi under uniform and tetragonal strains have been systematically studied by the first-principles calculation. Both Fe 2 NiSi and Ni 2 FeSi have the XA structure in cubic phase and they show metallic band structures and large magnetic moments (greater than 3 μ B ) at equilibrium condition. Tetragonal distortion can further decrease the total energy, leading to the possible phase transformation. Furthermore, different atom reordering behaviours have been observed: for Fe 2 NiSi, atoms reorder from cubic XA-type to tetragonal L1 0 -type; for Ni 2 FeSi, there is only structural transformation without atom reordering. The total magnetic moments of Fe 2 NiSi and Ni 2 FeSi are mainly contributed by Fe atoms, and Si atom can strongly suppress the moments of Fe atoms when it is present in the nearest neighbours of Fe atoms. With the applied strain, the distance between Fe and Si atoms play an important role for the magnetic moment variation of Fe atom. Moreover, the metallic band nature is maintained for Fe 2 NiSi and Ni 2 FeSi under both uniform and tetragonal strains. This study provides a detailed theoretical analysis about the full Heusler compounds Fe 2 NiSi and Ni 2 FeSi under strain conditions.

First-Principles Prediction of Structural, Magnetic, Electronic, and Elastic Properties of Full-Heusler Compounds Co2YIn (Y = Ti, V)

2016 ◽  
Vol 29 (9) ◽  
pp. 2225-2233 ◽  
Author(s):  
Salah Khenchoul ◽  
Abdelnasser Guibadj ◽  
Brahim Lagoun ◽  
Abdelhakim Chadli ◽  
Said Maabed
Keyword(s):  
Elastic Properties ◽  
First Principles ◽  
Heusler Compounds ◽  
Full Heusler

scholarly journals Design ofL21-type antiferromagnetic semiconducting full-Heusler compounds: A first principles DFT + GWstudy

2017 ◽  
Vol 121 (5) ◽  
pp. 053903 ◽  
Author(s):  
M. Tas ◽  
E. Şaşıoğlu ◽  
C. Friedrich ◽  
S. Blügel ◽  
I. Galanakis
Keyword(s):  
First Principles ◽  
Heusler Compounds ◽  
Full Heusler

First-principles calculations to investigate structural, electronic and optical properties of (ZnSe)n/(ZnTe)n superlattices

2020 ◽  
Author(s):  
Messaoud Caid
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Correlation Energy ◽  
Local Density ◽  
Full Potential ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Lmto Method ◽  
Binary Compounds

An investigation into the structural, electronic and optical properties of superlattices(SLs) (ZnSe)n/(ZnTe)n was conducted using first principles calculations based on density functional theory (DFT). The total energies were calculated within the full-potential linear muffin-tin orbital (FP-LMTO) method augmented by a plane-wave basis (PLW), implemented in LmtART 7.0 code. The effects of the approximations to the exchange-correlation energy were treated by the local density approximation (LDA). The ground state properties of (ZnSe)n/(ZnTe)n binary compounds are determined and compared with the available data. It is found that the superlattice (n-n: 1-1, 2-2 and 3-3) band gaps vary depending on the layers used. The optical constants, including the dielectric function ε(w), the refractive index n(w) and the reflectivity R(w), are calculated for radiation energies up to 35eV.

scholarly journals Electronic structure and thermoelectric properties of full Heusler compounds Ca2YZ (Y = Au, Hg; Z = As, Sb, Bi, Sn and Pb)

RSC Advances ◽  
2020 ◽  
Vol 10 (48) ◽  
pp. 28501-28508
Author(s):  
Yang Hu ◽  
Yurong Jin ◽  
Guangbiao Zhang ◽  
Yuli Yan
Keyword(s):  
Electronic Structure ◽  
Transport Properties ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Transport Theory ◽  
Combination Method ◽  
Heusler Compounds ◽  
Boltzmann Transport ◽  
Boltzmann Transport Theory ◽  
Full Heusler

We investigate the transport properties of bulk Ca2YZ (Y = Au, Hg; Z = As, Sb, Bi, Sn and Pb) by a combination method of first-principles and Boltzmann transport theory.

First-Principles Simulations of Interstitial Atoms in Ionic Solids

1995 ◽  
Vol 408 ◽  
Author(s):  
E. A. Kotomin ◽  
A. Svane ◽  
T. Brudevoll ◽  
W. Schulz ◽  
N. E. Christensen
Keyword(s):  
Experimental Data ◽  
First Principles ◽  
Recent Experimental Data ◽  
Full Potential ◽  
Ionic Solids ◽  
Interstitial Atoms ◽  
Lmto Method ◽  
Radiation Induced ◽  
Anion Site ◽  
Molecular Mode

The atomic and electronic structure of the radiation-induced interstitial atoms in MgO and KCl crystals representing two broad classes of ionic solids are calculated and compared. The first-principles full potential LMTO method is applied to a 16-atom supercell. For both crystals the energetically most favourable configuration is a dumbbell centered at a regular anion site. Its (110) and (111) orientations are very close in energy which permits the dumbbell to rotate easily on a lattice site. The mechanism and the relevant activation energy for thermally activated diffusion hops from the dumbbell equilibrium position to the cube face and cube center are discussed in the light of the available experimental data for MgO. In order to interpret recent experimental data on Raman spectroscopy, the local vibrational frequences are calculated for the dumbbell in KCl (the so-called H center). A strong coupling is found between its stretching molecular mode and the breathing mode of the nearest cations whose frequency is predicted.

Structural and Electronic Properties of a Thin Metal-Silicide Film on Silicon Surface: A First-Principles Study

2003 ◽  
Vol 10 (02n03) ◽  
pp. 183-188 ◽  
Author(s):  
Byung Sub Kang ◽  
Hee Jae Kang ◽  
Suhk Kun Oh
Keyword(s):  
Electronic Properties ◽  
Structural Stability ◽  
First Principles ◽  
Structural Model ◽  
Surface Model ◽  
Full Potential ◽  
Surface And Interface ◽  
Structural And Electronic Properties ◽  
Lmto Method ◽  
Theoretical Results

The structural stability of metal (M) silicide (M = Co, Ni) phases and magnetic properties for the deposited one and two monolayers (ML) of M on the Si(001) surface was studied by the use of the ab initio full-potential linear muffin-tin orbital (FP-LMTO) method. The diffusion of M atoms on Si into the tetrahedral (fourfold M) sites was found to be energetically favorable. The deposited M atoms easily migrate into the bulk because the diffusion or interchange is energetically more favorable than the formation of cluster in a surface layer. The energetics for the structural stability of the "fourfold Si surface" model was compared with that of the sixfold structural model. Our results for the electronic properties of the MSi2/Si(001) surface and interface were compared with experimental and other theoretical results.

Physical Properties of RhCrZ (Z= Si, Ge, P, As) Half-Heusler Compounds: A First-Principles Study

2020 ◽  
Vol 13 (1) ◽  
pp. 29-46
Keyword(s):  
Thermoelectric Properties ◽  
First Principles ◽  
Density Functional ◽  
Structural Parameters ◽  
Mean Field Approximation ◽  
Cubic Phase ◽  
Full Potential ◽  
Heusler Compounds ◽  
Half Metallicity ◽  
Half Metallic

We use the first-principles-based density functional theory with full potential linearized augmented plane wave method in order to investigate the structural, elastic, electronic, magnetic and thermoelectric properties of RhCrZ (Z= Si, Ge, P, As) Half-Heusler compounds. The preferred configurations of the RhCrZ alloys are all type a. The structural parameters are in good agreement with the available theoretical results. The Young’s and shear modulus, Poisson’s ratio, sound velocities, Debye temperature and melting temperature have been calculated. Furthermore, the elastic constants Cij and the related elastic moduli confirm their stability in the cubic phase and demonstrate their ductile nature. The compounds RhCrSi, RhCrGe, RhCrP and RhCrAs are found to be half-metallic ferrimagnets (HMFs) with a half-metallic gap EHM of 0.37, 0.35, 0.25 and 0.02 eV, respectively. The half-metallicity of RhCrZ (Z= Si, Ge, P, As) compounds can be kept in a quite large hydrostatic strain and tetragonal distortion. The Curie temperatures of RhCrSi, RhCrGe, RhCrP and RhCrAs compounds are estimated to be 952, 1261, 82 and 297 K, respectively, in the mean field approximation (MFA). Thermoelectric properties of the RhCrZ (Z= Si, Ge, P, As) materials are additionally computed over an extensive variety of temperatures and it is discovered that RhCrAs demonstrates higher figure of merit than RhCrSi, RhCrGe and RhCrP. The properties of half-metallicity and higher Seebeck coefficient make this material a promising candidate for thermoelectric and spintronic device applications

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