scholarly journals Влияние уровней Ландау на ССТС спектров ЭПР преципитатов Fe-=SUP=-3+-=/SUP=- в дираковском 3D-полуметалле Cd-=SUB=-3-=/SUB=-As-=SUB=-2-=/SUB=-

2020 ◽  
Vol 62 (1) ◽  
pp. 78
Author(s):  
Ю.В. Горюнов ◽  
А.Н. Натепров
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Density Of States ◽  
Main Type ◽  
Contact Potential Difference ◽  
Landau Levels ◽  
Contact Potential ◽  
Metal Impurities ◽  
Magneto Resistance ◽  
Fe Impurity

The influence of d-metal impurities on the magnetic and transport properties of the 3D topological Cd3As2 semimetal is experimentally studied. It was found that when doping with iron, unlike Eu, there is no change in the sign of magneto resistance. There is an increase in the oscillations of the quantities (magnetic susceptibility, contact potential difference, and conductivity) associated with oscillations in the density of states at the Fermi level with temperature and magnetic field. In the temperature range of 10–300 K, EPR signals from Fe2+ ions were not detected, although, most likely, are the main type of Fe impurity in Cd3As2. From Fe3+ ions, weak EPR signals with a super-hyperfine structure (SHFS) were observed, which are obviously effected by Landau levels.

MATHEMATICAL MODELING OF TEMPERATURE EFFECT ON THE FAN CHART OF MAGNETOABSORPTION SPECTRUM IN SEMICONDUCTORS

2019 ◽  
pp. 104-115
Author(s):  
G. Gulyamov ◽  
U. I. Erkaboev ◽  
A. G. Gulyamov
Keyword(s):  
Mathematical Modeling ◽  
Magnetic Field ◽  
Temperature Dependence ◽  
Density Of States ◽  
Landau Levels ◽  
Joint Density ◽  
Narrow Gap ◽  
Narrow Gap Semiconductors ◽  
Dispersion Law ◽  
The Magnetic Field

The article considers the oscillations of interband magneto-optical absorption in semiconductors with the Kane dispersion law. We have compared the changes in oscillations of the joint density of states with respect to the photon energy for different Landau levels in parabolic and non-parabolic zones. An analytical expression is obtained for the oscillation of the combined density of states in narrow-gap semiconductors. We have calculated the dependence of the maximum photon energy on the magnetic field at different temperatures. A theoretical study of the band structure showed that the magnetoabsorption oscillations decrease with an increase in temperature, and the photon energies nonlinearly depend on a strong magnetic field. The article proposes a simple method for calculating the oscillation of joint density of states in a quantizing magnetic field with the non-quadratic dispersion law. The temperature dependence of the oscillations joint density of states in semiconductors with non-parabolic dispersion law is obtained. Moreover, the article studies the temperature dependence of the band gap in a strong magnetic field with the non-quadratic dispersion law. The method is applied to the research of the magnetic absorption in narrow-gap semiconductors with nonparabolic dispersion law. It is shown that as the temperature increases, Landau levels are washed away due to thermal broadening and density of states turns into a density of states without a magnetic field. Using the mathematical model, the temperature dependence of the density distribution of energy states in strong magnetic fields is considered. It is shown that the continuous spectrum of the density of states, measured at the temperature of liquid nitrogen, at low temperatures turns into discrete Landau levels. Mathematical modeling of processes using experimental values of the continuous spectrum of the density of states makes it possible to calculate discrete Landau levels. We have created the three-dimensional fan chart of magneto optical oscillations of semiconductors with considering for the joint density of energy states. For a nonquadratic dispersion law, the maximum frequency of the absorbed light and the width of the forbidden band are shown to depend nonlinearly on the magnetic field. Modeling the temperature  dependence allowed us to determine the Landau levels in semiconductors in a wide temperature spectrum. Using the proposed model, the experimental results obtained for narrow-gap semiconductors are analyzed. The theoretical results are compared with experimental results.

scholarly journals Magneto-optic signatures in the gapped Dirac semimetal with mixed linear and parabolic dispersions of ZrTe5

2021 ◽  
Author(s):  
Le You ◽  
Zi-Yue Zhang ◽  
Yi-Xiang Wang
Keyword(s):  
Magnetic Field ◽  
Density Of States ◽  
Optical Conductivity ◽  
Theoretical Study ◽  
Saddle Points ◽  
Three Dimensional ◽  
Landau Levels ◽  
Dirac Semimetal ◽  
The Magnetic Field ◽  
Good Agreement

Abstract In this paper, we give a systematic theoretical study on the Landau levels (LLs) and magneto-optical conductivity Re(σαα) in a gapped Dirac semimetal model with mixed linear and parabolic dispersions under a magnetic field, which was recently proposed by Jiang et al. [Phys. Rev. Lett. 125, 046403 (2020)] to explain the experimental magnetoinfrared spectroscopy in the three-dimensional ZrTe5 crystal. We find that the strong magnetic field can drive the LLs become noninverted and thus the strong topological insulator phase in ZrTe5 turns to be a trivial insulator. In the different magnetic field regions, the density of states and Re(σαα) can exhibit distinct signatures. Moreover, when the magnetic field is weak, a qualitative relation in Re(σzz) between the peaks at the saddle points is revealed as Re(σzz ζn) >Re(σzz Γ) , which is in good agreement with the experiment.

scholarly journals Determination of the Density of Energy States in a Quantizing Magnetic Field for Model Kane

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
G. Gulyamov ◽  
U. I. Erkaboev ◽  
P. J. Baymatov
Keyword(s):  
Magnetic Field ◽  
Energy Density ◽  
Low Temperature ◽  
Density Of States ◽  
Landau Levels ◽  
Suggested Model ◽  
Dispersion Law ◽  
Energy States ◽  
Quantizing Magnetic Field

For nonparabolic dispersion law determined by the density of the energy states in a quantizing magnetic field, the dependence of the density of energy states on temperature in quantizing magnetic fields is studied with the nonquadratic dispersion law. Experimental results obtained for PbTe were analyzed using the suggested model. The continuous spectrum of the energy density of states at low temperature is transformed into discrete Landau levels.

PERIODIC AHARONOV–BOHM SOLENOIDS IN A CONSTANT MAGNETIC FIELD

2006 ◽  
Vol 18 (08) ◽  
pp. 913-934 ◽  
Author(s):  
TAKUYA MINE ◽  
YUJI NOMURA
Keyword(s):  
Magnetic Field ◽  
Landau Level ◽  
Density Of States ◽  
Homogeneous Magnetic Field ◽  
Landau Levels ◽  
Sufficient Condition ◽  
Absolutely Continuous ◽  
Lowest Landau Level ◽  
Aharonov Bohm ◽  
The Magnetic Field

We consider the magnetic Schrödinger operator on R2. The magnetic field is the sum of a homogeneous magnetic field and periodically varying pointlike magnetic fields on a lattice. We shall give a sufficient condition for each Landau level to be an infinitely degenerated eigenvalue. This condition is also necessary for the lowest Landau level. In the threshold case, we see that the spectrum near the lowest Landau level is purely absolutely continuous. Moreover, we shall give an estimate for the density of states for Landau levels and their gaps. The proof is based on the method of Geyler and Šťovíček, the magnetic Bloch theory, and canonical commutation relations.

The De Haas–Van Alphen effect at high temperatures and in low magnetic fields in semiconductors

2016 ◽  
Vol 30 (07) ◽  
pp. 1650077 ◽  
Author(s):  
G. Gulyamov ◽  
U. I. Erkaboev ◽  
N. Yu. Sharibaev
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Magnetic Fields ◽  
Temperature Dependence ◽  
High Temperatures ◽  
Density Of States ◽  
Effect Of Temperature ◽  
Method Of Calculation

We developed the method of calculation of the temperature dependence of the magnetic susceptibility. We considered the de Haas–van Alphen (dHvA) effect in semiconductors at high temperatures and low magnetic fields. The effect of temperature on dHvA effect is explained with respect to the temperature dependence of the thermodynamic density of states in a magnetic field.

An Augmented Iteratively Re-weighted and Refined Least Squares Method for lp Minimization Problem in Inverse Modeling of Potential Field Magnetic Data

2020 ◽  
Vol 1 (3) ◽  
Author(s):  
Maysam Abedi
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Least Squares ◽  
Minimization Problem ◽  
Potential Field ◽  
Field Data ◽  
Least Squares Method ◽  
Porphyry Copper ◽  
Magnetic Data ◽  
Magnetic Field Data

The presented work examines application of an Augmented Iteratively Re-weighted and Refined Least Squares method (AIRRLS) to construct a 3D magnetic susceptibility property from potential field magnetic anomalies. This algorithm replaces an lp minimization problem by a sequence of weighted linear systems in which the retrieved magnetic susceptibility model is successively converged to an optimum solution, while the regularization parameter is the stopping iteration numbers. To avoid the natural tendency of causative magnetic sources to concentrate at shallow depth, a prior depth weighting function is incorporated in the original formulation of the objective function. The speed of lp minimization problem is increased by inserting a pre-conditioner conjugate gradient method (PCCG) to solve the central system of equation in cases of large scale magnetic field data. It is assumed that there is no remanent magnetization since this study focuses on inversion of a geological structure with low magnetic susceptibility property. The method is applied on a multi-source noise-corrupted synthetic magnetic field data to demonstrate its suitability for 3D inversion, and then is applied to a real data pertaining to a geologically plausible porphyry copper unit.  The real case study located in  Semnan province of  Iran  consists  of  an arc-shaped  porphyry  andesite  covered  by  sedimentary  units  which  may  have  potential  of  mineral  occurrences, especially  porphyry copper. It is demonstrated that such structure extends down at depth, and consequently exploratory drilling is highly recommended for acquiring more pieces of information about its potential for ore-bearing mineralization.

scholarly journals Coupled Investigation of Contact Potential and Microstructure Evolution of Ultra-Thin AlOx for Crystalline Si Passivation

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1803
Author(s):  
Zhen Zheng ◽  
Junyang An ◽  
Ruiling Gong ◽  
Yuheng Zeng ◽  
Jichun Ye ◽  
...  
Keyword(s):  
Structural Changes ◽  
Silicon Oxide ◽  
Crystalline Silicon ◽  
Contact Potential Difference ◽  
Potential Difference ◽  
Kelvin Probe ◽  
Contact Potential ◽  
Carrier Lifetimes ◽  
Transmission Electron ◽  
Effective Carrier

In this work, we report the same trends for the contact potential difference measured by Kelvin probe force microscopy and the effective carrier lifetime on crystalline silicon (c-Si) wafers passivated by AlOx layers of different thicknesses and submitted to annealing under various conditions. The changes in contact potential difference values and in the effective carrier lifetimes of the wafers are discussed in view of structural changes of the c-Si/SiO2/AlOx interface thanks to high resolution transmission electron microscopy. Indeed, we observed the presence of a crystalline silicon oxide interfacial layer in as-deposited (200 °C) AlOx, and a phase transformation from crystalline to amorphous silicon oxide when they were annealed in vacuum at 300 °C.

Sign in / Sign up

Export Citation Format

Share Document