Ab initio full-potential study of the fundamental properties of chalcopyrite semiconductors XPN  2  (X = H, Cu)

ABSTRACTComplex quaternary chalcogenides (AgSb)xPbn-2xTen (0<x<n/2) are thought to be narrow band-gap semiconductors which are very good candidates for room and high temperature thermoelectric applications. These systems form in the rock-salt structure similar to the well known two component system PbTe (x=0). In these systems Ag and Sb occupy Pb sites randomly although there is some evidence of short-range order. To gain insights into the electronic structure of these compounds, we have performed electronic structure calculations in AgSbTe2 (x=n/2). These calculations were carried out within ab initio density functional theory (DFT) using full potential linearized augmented plane wave (LAPW) method. The generalized gradient approximation (GGA) was used to treat the exchange and correlation potential. Spinorbit interaction (SOI) was incorporated using a second variational procedure. Since it is difficult to treat disorder in ab initio calculations, we have used several ordered structures for AgSbTe2. All these structures show semimetallic behavior with a pseudogap near the Fermi energy. Te and Sb p orbitals, which are close in energy, hybridize rather strongly indicating a covalent interaction between Te and Sb atoms.

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Magnetic Properties and the Electronic Structure of the Gd0.4Tb0.6Co2 Compound

Materials ◽

10.3390/ma13235481 ◽

2020 ◽

Vol 13 (23) ◽

pp. 5481

Author(s):

Marcin Sikora ◽

Anna Bajorek ◽

Artur Chrobak ◽

Józef Deniszczyk ◽

Grzegorz Ziółkowski ◽

...

Keyword(s):

Electronic Structure ◽

Ab Initio Calculations ◽

Ab Initio ◽

Photoelectron Spectroscopy ◽

Density Functional ◽

Magnetic Measurements ◽

Plane Waves ◽

Full Potential ◽

Theory Approach ◽

Xps Spectra

We report on the comprehensive experimental and theoretical studies of magnetic and electronic structural properties of the Gd0.4Tb0.6Co2 compound crystallization in the cubic Laves phase (C15). We present new results and compare them to those reported earlier. The magnetic study was completed with electronic structure investigations. Based on magnetic isotherms, magnetic entropy change (ΔSM) was determined for many values of the magnetic field change (Δμ0H), which varied from 0.1 to 7 T. In each case, the ΔSM had a maximum around room temperature. The analysis of Arrott plots supplemented by a study of temperature dependency of Landau coefficients revealed that the compound undergoes a magnetic phase transition of the second type. From the M(T) dependency, the exchange integrals between rare-earth R-R (JRR), R-Co (JRCo), and Co-Co (JCoCo) atoms were evaluated within the mean-field theory approach. The electronic structure was determined using the X-ray photoelectron spectroscopy (XPS) method as well as by calculations using the density functional theory (DFT) based Full Potential Linearized Augmented Plane Waves (FP-LAPW) method. The comparison of results of ab initio calculations with the experimental data indicates that near TC the XPS spectrum collects excitations of electrons from Co3d states with different values of exchange splitting. The values of the magnetic moment on Co atoms determined from magnetic measurements, estimated from the XPS spectra, and results from ab initio calculations are quantitatively consistent.

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Full-potential study of d-electrons effects on the electronic structure of wurtzite and zinc-blende InN

physica status solidi (a) ◽

10.1002/pssa.200563515 ◽

2006 ◽

Vol 203 (1) ◽

pp. 35-41 ◽

Cited By ~ 8

Author(s):

F. Litimein ◽

B. Bouhafs ◽

P. Ruterana

Keyword(s):

Electronic Structure ◽

Full Potential ◽

Zinc Blende ◽

Potential Study

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Synthesis process, magnetic and electronic properties of ferrite nanoparticle MnFe2O4

Multidiscipline Modeling in Materials and Structures ◽

10.1108/mmms-07-2017-0068 ◽

2018 ◽

Vol 14 (4) ◽

pp. 663-675

Author(s):

R. Masrour ◽

M. Ben Ali ◽

H. El Moussaoui ◽

Mohamed Hamedoun ◽

A. Benyoussef ◽

...

Keyword(s):

Magnetic Properties ◽

Ab Initio ◽

Density Functional ◽

Synthesis Process ◽

Physical Parameters ◽

Full Potential ◽

Theory Approach ◽

Content Type ◽

Electronic And Magnetic Properties ◽

Ferrite Nanoparticle

Purpose The purpose of this paper is to synthesize the manganese ferrite nanoparticle MnFe2O4 and to investigate the structure, size and to study the electronic and the magnetic properties of MnFe2O4 nanoparticles. Design/methodology/approach The co-precipitation method is used to synthesize the MnFe2O4. The structure and size were investigated by X-ray diffraction. The superconducting quantum interference device is used to determine the some magnetic ground. From theoretical investigation point of view self-consistent ab initio calculations, based on density functional theory approach using full potential linear augmented plane wave method, were performed to investigate both electronic and magnetic properties of the MnFe2O4. The high temperatures series expansion (HTSE) is used to study the magnetic properties of MnFe2O4. Findings The saturation magnetization, the coercivity and the transition temperature varied between 21-43 emu/g, 20-50 Oe and 571-630 K, respectively, have been studied. The gap energy of MnFe2O4 has been deduced. The critical temperature and the critical exponent have been obtained using HTSEs. Originality/value In the present work, the authors study the electronic and magnetic properties of MnFe2O4. The results obtained by the experiment and by ab initio calculations were used in HTSE as input to deduce other physical parameters.

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AB-INITIO MOLECULAR DYNAMICS IN THE FULL-POTENTIAL LMTO METHOD: DERIVATION OF A PRACTICAL FORCE THEOREM

International Journal of Modern Physics B ◽

10.1142/s0217979293000573 ◽

1993 ◽

Vol 07 (01n03) ◽

pp. 262-265 ◽

Cited By ~ 68

Author(s):

M. METHFESSEL ◽

M. VAN SCHILFGAARDE

Keyword(s):

Molecular Dynamics ◽

Ab Initio ◽

Local Density ◽

Basis Set ◽

Ab Initio Molecular Dynamics ◽

Basis Sets ◽

Full Potential ◽

Major Advance ◽

First Results ◽

Lmto Method

A major advance in electronic structure calculations was the combination of local-density techniques with molecular dynamics by Car and Parrinello seven years ago. Unfortunately, application of the Car-Parrinello scheme has been limited essentially to sp materials because only in the plane-wave pseudopotential method forces are trivial to calculate. We present a systematic approach to derive force theorems with desired characteristics within complicated basis sets, which are applicable to all elements of the periodic table equally well. Application to the LMTO basis set yields an accurate force theorem, quite distinct from the Hellman-Feynman form, which is exceptionally insensitive to errors in the trial density. The forces were implemented in a new full-potential LMTO method which is suited to arbitrary geometries. First results for ab-initio molecular dynamics and simulated annealing runs are shown for some random small molecules and small clusters of silver atoms.

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