Effect of Pressure on Electronic Structure of Pb1−xSnxTe Alloys Doped with Gallium

2006 ◽  
Vol 929 ◽  
Author(s):  
Evgeny Pavlovich Skipetrov ◽  
Alexander Golubev ◽  
Nikolay Dmitriev ◽  
Vasily Slyn'ko
Keyword(s):  
Electronic Structure ◽  
Fermi Level ◽  
Alloy Composition ◽  
Matrix Composition ◽  
Free Electron Concentration ◽  
Resonant Level ◽  
Pressure Coefficients ◽  
Temperature Matrix ◽  
Band Dispersion ◽  
Galvanomagnetic Effects

ABSTRACTThe galvanomagnetic effects in the n-Pb1−xSnxTe:Ga (x=0.09-0.21) alloys at the temperatures 4.2≤T≤300 K and under hydrostatic compression up to 16 kbar have been investigated. It is shown that in all samples and in the whole investigated pressure range temperature dependencies of resistivity and Hall coefficient have a “metallic” character, indicating stabilization of Fermi level by the impurity resonant level. Using the experimental data in the frame of two-band dispersion law the dependencies of the free electron concentration and the Fermi level position upon temperature, matrix composition and pressure were calculated. The temperature, composition and pressure coefficients of gallium resonant level movement were obtained and the electronic structure under varying the alloy composition and under pressure were built.

Chromium Impurity States in Pb1-xGexTe Alloys Under Pressure

2006 ◽  
Vol 987 ◽  
Author(s):  
Evgeny Skipetrov ◽  
Alexey Plastun ◽  
Boris Kovalev ◽  
Lyudmila Skipetrova ◽  
Tatyana Topchevskaya ◽  
...  
Keyword(s):  
Alloy Composition ◽  
Deep Level ◽  
Matrix Composition ◽  
Free Electron Concentration ◽  
Metal Insulator ◽  
Germanium Content ◽  
Impurity States ◽  
Insulator Metal Transition ◽  
The Matrix ◽  
Galvanomagnetic Effects

AbstractThe galvanomagnetic effects in the n-Pb1-xGexTe:Cr (x=0.02-0.13) alloys at the temperatures 4.2≤T≤300 K and under hydrostatic compression up to 17 kbar have been investigated. The metal-insulator transition under the increase of germanium content in the alloys and insulator-metal transition, induced by pressure in Pb1-xGexTe:Cr (x=0.10) alloy, were revealed. Using the experimental data in the frame of two-band Kane dispersion relation the dependences of the free electron concentration and the Fermi level position on the matrix composition and on the pressure were calculated. The composition and pressure coefficients of chromium deep level movement were obtained and the models of the electronic structure reconstruction under varying the alloy composition and under pressure were proposed.

Galvanomagnetic and Magnetic Properties of Pb1-yScyTe

2015 ◽  
Vol 233-234 ◽  
pp. 97-100 ◽  
Author(s):  
E.P. Skipetrov ◽  
M.M. Markina ◽  
K.V. Zakharov ◽  
L.A. Skipetrova ◽  
A.A. Solovev ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Electronic Structure ◽  
Impurity Content ◽  
Free Electron Concentration ◽  
Resonant Level ◽  
Structure Rearrangement ◽  
Galvanomagnetic Properties ◽  
Weak Magnetic Fields ◽  
Heavily Doped

The galvanomagnetic properties in weak magnetic fields (4.2≤T≤300 K, B≤0.07 T) as well as magnetic properties (2≤T≤300 K, B≤9 T) of the single-crystal Pb1-yScyTe (y≤0.02) alloys have been investigated. We find that an increase of Sc impurity content leads to a monotonous growth of the free electron concentration (from 1016 cm-3 to 1020 cm-3). In heavily doped alloys (y>0.01), it tends to saturation, indicating the pinning of the Fermi energy by the scandium resonant level located inside the conduction band. The energy of the level is estimated (ESc≈Ec+280 meV) and the model of electronic structure rearrangement of Pb1-yScyTe alloys with doping is proposed. In the frame of this model, using experimental temperature and magnetic field dependences of magnetization, the concentrations of magnetically active scandium ions are determined and connection of the electronic structure with the magnetic properties of the alloys are discussed.

Magnetic Ground State and Electronic Structure Calculations of PbMnO3 Using DFT

2014 ◽  
Vol 895 ◽  
pp. 420-423 ◽  
Author(s):  
Sathya Sheela Subramanian ◽  
Baskaran Natesan
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Fermi Level ◽  
Ground State ◽  
Density Functional ◽  
Electronic Structure Calculations ◽  
Magnetic Ground State ◽  
Electronic Band ◽  
Structure Calculations ◽  
Centrosymmetric Structure

Structural optimization, magnetic ground state and electronic structure calculations of tetragonal PbMnO3have been carried out using local density approximation (LDA) implementations of density functional theory (DFT). Structural optimizations were done on tetragonal P4mm (non-centrosymmetric) and P4/mmm (centrosymmetric) structures using experimental lattice parameters and our results indicate that P4mm is more stable than P4/mmm. In order to determine the stable magnetic ground state of PbMnO3, total energies for different magnetic configurations such as nonmagnetic (NM), ferromagnetic (FM) and antiferromagnetic (AFM) were computed for both P4mm and P4/mmm structures. The total energy results reveal that the FM non-centrosymmetric structure is found to be the most stable magnetic ground state. The electronic band structure, density of states (DOS) and the electron localization function (ELF) were calculated for the stable FM structure. ELF revealed the distorted non-centrosymmetric structure. The band structure and DOS for the majority spins of FM PbMnO3showed no band gap at the Fermi level. However, a gap opens up at the Fermi level in minority spin channel suggesting that it could be a half-metal and a potential spintronic candidate.

Synthesis, crystal and electronic structure of BaLi2Cd2Ge2

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sviatoslav Baranets ◽  
Alexander Ovchinnikov ◽  
Svilen Bobev
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Fermi Level ◽  
Structure Type ◽  
Layered Crystal ◽  
Electronic Density ◽  
Electronic Band ◽  
Cell Parameters ◽  
Layered Crystal Structure ◽  
Electronic Band Gap

Abstract A new quaternary germanide has been synthesized and structurally characterized. BaLi2Cd2Ge2 adopts the rhombohedral CaCu4P2 structure type (Pearson code hR7; space group R 3 ‾ m $R‾{3}m$ , Z = 3) with unit cell parameters a = 4.5929(6) and c = 26.119(5) Å. Structure refinements from single-crystal X-ray diffraction data demonstrate that the layered crystal structure can be regarded as an ordered quaternary variant of the ternary archetype; structural parallels to layered pnictides and binary germanides can also be drawn. The layered crystal structure is characterized by the absence of direct Ge–Ge and Cd–Cd homoatomic bonds, which suggests that BaLi2Cd2Ge2 should be classified as a Zintl phase, according to the formulation (Ba2+)(Li+)2(Cd2+)2(Ge4−)2. Electronic structure calculations show that the Fermi level crosses a distinct peak in the DOS, although the presence of an electronic band gap or a dip in the electronic density of states at the Fermi level is expected based on the electron partitioning.

Relation between oxygen stoichiometry and thermodynamic properties and the electronic structure of nonstoichiometric perovskite La0.6Sr0.4CoO3−δ

2016 ◽  
Vol 18 (42) ◽  
pp. 29543-29548 ◽  
Author(s):  
S. F. Bychkov ◽  
A. G. Sokolov ◽  
M. P. Popov ◽  
A. P. Nemudry
Keyword(s):  
Electronic Structure ◽  
Thermodynamic Properties ◽  
Fermi Level ◽  
Electronic States ◽  
Oxygen Activity ◽  
Oxygen Stoichiometry ◽  
Itinerant Electron ◽  
Electron Model ◽  
Density Of Electronic States

Within the framework of the itinerant electron model, the dependence of the oxide nonstoichiometry on the oxygen activity was related to the density of electronic states near the Fermi level.

EFFECT OF THE LOCAL SUBSTITUTION OF Co FOR Cu(1) ON THE ELECTRONIC STRUCTURE OF YBa2Cu3O7

1993 ◽  
Vol 07 (07) ◽  
pp. 471-481 ◽  
Author(s):  
JIU-YUAN GE ◽  
YUN-SONG ZHOU ◽  
LI-YUAN ZHONG ◽  
HUAI-YU WANG
Keyword(s):  
Electronic Structure ◽  
Fermi Level ◽  
Density Of States ◽  
Recursion Method ◽  
Electronic Density ◽  
One Dimensional ◽  
Electronic Density Of States ◽  
Co Doping

The electronic density of states (DOS) of both pure and Co-substituted YBa 2 Cu 3 O 7 has been calculated by a recursion method. The results show that the total DOS at the Fermi level of YBa 2 Cu 3 O 7 mainly comes from the contributions of the O 2p and Cu 3d orbitals. After Co doping, the O 2p–Cu 3d bonds are destroyed while the O 2p–Co 3d bonds are formed at lower energies, and the total DOS at the Fermi level decreases strikingly. In addition, our results reveal that the CuO chain has a one-dimensional feature.

Structural and Magnetic Study on the Effect of Substitution of Cobalt by d-Valent Elements of Co2FeSi Heusler Alloy

2016 ◽  
Vol 708 ◽  
pp. 37-41
Author(s):  
Muhammad Noor Syazwan Saimin ◽  
Siti Sumaiyah Sheikh Abdul Aziz ◽  
A.M.M. Ali ◽  
Oskar Hasdinor Hassan ◽  
Muhd Zu Azhan Yahya ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
Band Structure ◽  
Fermi Level ◽  
Density Of States ◽  
Magnetic Moment ◽  
Local Magnetic Moment ◽  
Half Metallic ◽  
New States ◽  
Full Heusler

In this paper, the effect of substitution of Co by d-valent elements such as Ag and Pt on electronic structure and magnetic properties of full Heusler type Co2FeSi alloys was investigated. Structural study reveals the presence of a small gap in the minority band structure around the vicinity of the Fermi level on Co2FeSi resulting to half-metallic behaviour. However, CoFeSiAg and CoFeSiPt cannot preserved the half-metalicity due to disappearing of the gap in the minority band structure due to the creation of new states around the Fermi level in the minority density of states. The variation in the magnetic moment of Co2FeSi with change of the atoms was attributed to the change in the local magnetic moment of atoms.

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