On The Field Fmisiicn Fwom HgTe-CdTe Superlarrices with Graded Struijctures Under Magnetic Quantization

1989 ◽  
Vol 161 ◽  
Author(s):  
Kamakhya P. Ghatak ◽  
Sambjij N Biswas
Keyword(s):  
Magnetic Field ◽  
Experimental Observation ◽  
Field Emission ◽  
Electron Concentration ◽  
Current Density ◽  
Graded Structure ◽  
Magnetic Quantization ◽  
Theoretical Results

ABSTRACTIn this paper, we studied the magneto-field emission from HgTe/Cdre superlattices with graded structure and compared the same with the bulk specimens of the constituent materials. It is found that the field emitted current density increases both with electron concentration and magnetic field in an oscillatory manner. The field emission in HgTe/CdTe SLi is greater than that of the same from constituent materials the theoretical results are in agreement with the experimental observation as reported elsewhere.

On the Thermoelectric Power in Quantum Dots of Non-Parabolic Semiconductors in Thr Presence of a Classically Large Field

1990 ◽  
Vol 198 ◽  
Author(s):  
Ktamkahya P. Ghatak ◽  
B. De ◽  
M. Mondal ◽  
S.N. Biswas
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
Film Thickness ◽  
Thermoelectric Power ◽  
Experimental Observation ◽  
Electron Concentration ◽  
Large Field ◽  
Large Magnetic Field ◽  
Theoretical Results

ABSTRACTWe have studied the thermoelectric power in quantum dots (QDs) of non-parabolic semiconductors in the presence of a classically large magnetic field and we have taken A3N B2V, ternary chalcopyrite, II-VI and III-V semiconductors. It is found that the thermopower increases with increasing film thickness and decreasing electron concentration respectively in all the cases. The numerical values are greatest for Cd3As2 and least for InAs and the theoretical results are in ageement with the experimental observation as reported elsewhere.

The Effect of Thermal Accumulation to the Field Emission Properties of the Carbon Nanotubes

2015 ◽  
Vol 645-646 ◽  
pp. 265-268
Author(s):  
Fei Yan ◽  
Nan Nan Li ◽  
Lei Chen ◽  
Da Zhi Jin ◽  
Wei Xiang
Keyword(s):  
Carbon Nanotubes ◽  
Experimental Observation ◽  
Field Emission ◽  
Current Density ◽  
Pulse Mode ◽  
Emission Characteristics ◽  
Emission Properties ◽  
Good Linear ◽  
Field Emission Properties ◽  
Linear Fit

In this paper, we report a recent experimental observation of the effect of thermal accumulation to the field emission properties of the carbon nanotubes. The carbon nanotubes are grown on Ni by CVD. We compare the field emission characteristics of carbon nanotubes cathodes under DC and pulse mode. Our research shows that the higher current and higher current density could be acquired by suppressing the thermal accumulation. The Fowler-Nordheim plot shows a good linear fit, indicating that the emission current of carbon nanotubes follows Fowler-Nordheim behavior.

The Diffusivity-Mobilitt Ratio Under Strong Magnetic Field in III-V Superlattices with Graded Structures

1993 ◽  
Vol 300 ◽  
Author(s):  
Kamakhya P. Ghatak ◽  
Badal De
Keyword(s):  
Magnetic Field ◽  
Experimental Method ◽  
Strong Magnetic Field ◽  
Mobility Ratio ◽  
Einstein Relation ◽  
Dispersion Law ◽  
Magnetic Quantization ◽  
Graded Structures ◽  
Theoretical Results

ABSTRACTIn this paper we have studied the Einstein relation for the diffusivity-mobility ratio in III-V superlattices with graded structures under magnetic quantization by formulating a new dispersion law. It is found, taking InAs/GaSb an example that the diffusivity mobility ratio increases in an oscillatory way with increasing carrier degeneracy as a consequence4SdH effect. The Einstein relation in IIIV superlattice is greater than that of the same for the constituent materials. Besides the theoretical results are in agreement with the suggested experimental method of determining the same ratio in degenerate materials having arbitrary dispersion laws.

The Photoemission from Superlattices of III-V Semiconductors with Graded Interfaces Under Quantizing Magnetic Field

1994 ◽  
Vol 299 ◽  
Author(s):  
Kamakhya P. Ghatak ◽  
Badal De
Keyword(s):  
Magnetic Field ◽  
Theoretical Analysis ◽  
Electron Concentration ◽  
Quantum Limit ◽  
Super Lattice ◽  
Dispersion Law ◽  
Magnetic Quantization ◽  
Wide Gap ◽  
Quantizing Magnetic Field

AbstractIn this paper we have studied the photoemission from super-lattices of III-V semiconductors under magnetic quantization by formulating a new dispersion law. It is found, taking InAs/GaSb super-lattice with graded interfaces as an example that the photoemission, increases with increasing electron concentration in an oscillatory way and increases with decreasing magnetic field in the magnetic quantum limit. Besides, the photoemission in superlattices is much greater than that of the constituent materials and the well-known results for wide-gap materials have also been obtained from our generalized analysis. In addition, the theoretical analysis is in agreement with the experimental datas as given elsewhere.

On the Thermoelectric Power in Ultrathin Films of A3IIB2V Semiconductors Under Magnetic Quantization

1991 ◽  
Vol 234 ◽  
Author(s):  
Kamakhya P. Ghatak ◽  
Badal De
Keyword(s):  
Energy Spectrum ◽  
Film Thickness ◽  
Thermoelectric Power ◽  
Electron Concentration ◽  
Ultrathin Films ◽  
Surface Electron ◽  
Magnetic Quantization ◽  
Theoretical Results

ABSTRACTAn attempt is made to study the thermoelectric power in ultrathin films of semiconductors under magnetic quantization by including all types of aniso tropies in the energy spectrum within the domain of theory, and taking n-Cd3As2 as an example. It is found that, the magne to-thermopower decreases with increasing surface electron concentration and also changes in an oscillatory manner with film thickness respectively. The theoretical results are in agreement with the experimental observations as reported elsewhere.

The Diffusivtty-Mobility Ratio Under Strong Magnetic Field in Small Gap Superlattices with Graded Structures

1992 ◽  
Vol 262 ◽  
Author(s):  
Kamakhya P. Ghatak ◽  
Badal De
Keyword(s):  
Magnetic Field ◽  
Experimental Method ◽  
Strong Magnetic Field ◽  
Mobility Ratio ◽  
Einstein Relation ◽  
Dispersion Law ◽  
Magnetic Quantization ◽  
Graded Structures ◽  
Theoretical Results

ABSTRACTIn this paper we have studied the Einstein relation for the diffusivity-mobllity ratio (DMR) in small-gap superi at tices (SLS) with graded structures under magnetic quantization by formulating a new dispersion law. It is found, taking inAs/ GaSb SL as an example that the DMR increases in an oscillatory way with increasing carrier degeneracy due to SdH effect. The DMR in SL. is greater than that of the constituent materials. The theoretical results are in agreement with the suggested experimental method of determining the DMR in degenerate materials having arbitrary dispersion laws.

scholarly journals Magnetic nulls in interacting dipolar fields

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Todd Elder ◽  
Allen H. Boozer
Keyword(s):  
Magnetic Field ◽  
Current Density ◽  
Magnetic Flux Tube ◽  
Electron Inertia ◽  
Characteristic Spatial Scale ◽  
Field Lines ◽  
Dipolar Fields ◽  
Time Required ◽  
Magnetic Null ◽  
The Magnetic Field

The prominence of nulls in reconnection theory is due to the expected singular current density and the indeterminacy of field lines at a magnetic null. Electron inertia changes the implications of both features. Magnetic field lines are distinguishable only when their distance of closest approach exceeds a distance $\varDelta _d$ . Electron inertia ensures $\varDelta _d\gtrsim c/\omega _{pe}$ . The lines that lie within a magnetic flux tube of radius $\varDelta _d$ at the place where the field strength $B$ is strongest are fundamentally indistinguishable. If the tube, somewhere along its length, encloses a point where $B=0$ vanishes, then distinguishable lines come no closer to the null than $\approx (a^2c/\omega _{pe})^{1/3}$ , where $a$ is a characteristic spatial scale of the magnetic field. The behaviour of the magnetic field lines in the presence of nulls is studied for a dipole embedded in a spatially constant magnetic field. In addition to the implications of distinguishability, a constraint on the current density at a null is obtained, and the time required for thin current sheets to arise is derived.

scholarly journals The effect of simplifications of a numerical mesh on the results of electromagnetic analysis of the Nuclotron-type cable

2018 ◽  
Vol 177 ◽  
pp. 08004
Author(s):  
Łukasz Tomków
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Current Density ◽  
Electric Current Density ◽  
Electromagnetic Analysis ◽  
First Case ◽  
Single Region ◽  
The Magnetic Field

The model of a single Nuclotron-type cable is presented. The goal of this model is to assess the behaviour of the cable under different loads. Two meshes with different simplifications are applied. In the first case, the superconductor in the cable is modelled as single region. Second mesh considers individual strands of the cable. The significant differences between the distributions of the electric current density obtained with both models are observed. The magnetic field remains roughly similar.

Thermoelectric Power in Quantum Confined Bismuth Under Classically Large Magnetic Field

1990 ◽  
Vol 216 ◽  
Author(s):  
Kamakhya P. Ghatak ◽  
S. N. Biswas
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
Quantum Well ◽  
Film Thickness ◽  
Quantum Wells ◽  
Thermoelectric Power ◽  
Large Magnetic Field ◽  
Quantum Well Wires ◽  
Electron Dispersion ◽  
Theoretical Results

ABSTRACTIn this paper we studied the thermoelectric power under classically large magnetic field (TPM) in quantum wells (QWs), quantum well wires (QWWS) and quantum dots (QDs) of Bi by formulating the respective electron dispersion laws. The TPM increases with increasing film thickness in an oscillatory manner in all the cases. The TPM in QD is greatest and the least for quantum wells respectively. The theoretical results are in agreement with the experimental observations as reported elsewhere.

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