On The Thermoelectric Power in Degenerate Narrow Gap Semiconductors in the Presence of a Strong Magnetic Field

1991 ◽  
Vol 234 ◽  
Author(s):  
Kamakhya Prasad Ghatak ◽  
Badal De
Keyword(s):  
Magnetic Field ◽  
Thermoelectric Power ◽  
Effective Mass ◽  
Strong Magnetic Field ◽  
Fourth Order ◽  
Narrow Gap ◽  
Energy Bands ◽  
Degenerate Semiconductors ◽  
Conduction Electrons ◽  
Special Cases

ABSTRACTIn this paper we have studied the thermoelectric power under strong magnetic field in degenerate semiconductors on the basis of fourth order in effective mass theory and taking into account the interactions of the conduction electrons, heavy-holes, light-holes and split-off holes respectively. The results obtained are then compared to those derived on the basis of the well-known three-band Kane model. It is found, taking n-Hg1-xCdxTe as an example, that the magneto-thermo power increases with decreasing electron concentration and increasing magnetic field respectively for both the models in an oscillatory way. The oscillations are due to SdH effects and the theoretical snelysis in accordance with fourth order in effective mass theory is in agreement with the experimental observation as reported elsewhere. In addition, the corresponding results for parabolic energy bands have also been obtained as special cases of our generalized foriulations.

scholarly journals The theory of the galvanomagnetic and thermomagnetic effects in metals

1948 ◽  
Vol 193 (1035) ◽  
pp. 484-512 ◽  
Keyword(s):  
Magnetic Field ◽  
Thermoelectric Power ◽  
High Temperatures ◽  
Low Temperatures ◽  
Band Model ◽  
Energy Bands ◽  
Free Electrons ◽  
Special Cases ◽  
Theoretical Predictions ◽  
Pass Through

The methods of a previous paper are used to discuss the effect of a magnetic field on the thermoelectric power of a metal containing two overlapping energy bands of normal form. Exact solutions of the transport equation are obtained for the three limiting cases of high temperatures, low temperatures and very strong magnetic fields, and it is shown that the formulae can be generalized to give approximate expressions for all temperatures and all fields. The magnetic change of the thermoelectric power is found to be small at very low and high temperatures, and to pass through a maximum at intermediate temperatures. The transverse galvano- and thermomagnetic effects are also considered, and the formulae which hold for free electrons are generalized so as to be approximately valid for all temperatures. For free electrons, the Hall coefficient remains constant as the temperature decreases, the Righi-Leduc coefficient increases, and the Ettingshausen and Ettingshausen-Nemst coefficients decrease and change sign at very low temperatures. The corresponding formulae for a metal containing two bands are also obtained, and are used to show that the theoretical predictions for free electrons cannot hold for real metals except in special cases. Finally, the two-band model is used to discuss the effect of the magnitude of the magnetic field on the coefficients of the transverse effects.

Magneto-optical studies of shallow donors in MOCVD grown GaN layers in FIR

1998 ◽  
Vol 3 ◽  
Author(s):  
A. M. Witowski ◽  
M. L. Sadowski ◽  
K. Paku ,a ◽  
B. Suchanek ◽  
R. Stepniewski ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Effective Mass ◽  
Ionization Energy ◽  
Far Infrared ◽  
Optical Studies ◽  
Conduction Electrons ◽  
Shallow Donors ◽  
State Splitting ◽  
Si Doped

Far infrared magnetooptical investigations of shallow donors in epitaxial MOCVD GaN layers show two types of shallow donors. In relaxed layers, a donor with an ionization energy of 35 meV was found. In strained, undoped and Si doped samples, a donor with ionization energy 32.5 meV was observed. From the p state splitting in magnetic field, the cyclotron effective mass for conduction electrons was found to be m*=0.222 m0.

Transporteigenschaften und Quantenoszillationen von Te-und Sn-dotiertem Bi94Sb6 / Transport Properties and Quantum Oscillations of Te- and Sn-Doped Bi94Sb6

1975 ◽  
Vol 30 (8) ◽  
pp. 1071-1083
Author(s):  
G. Schneider ◽  
R. Trommer
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Transport Properties ◽  
Thermoelectric Power ◽  
Effective Mass ◽  
Quantum Oscillations ◽  
Mobility Tensor ◽  
Mass Tensor ◽  
Approximate Composition ◽  
Shubnikov De Haas Oscillations

Abstract Electronic transport properties of undoped, Te- and Sn-doped Bi-Sb-alloys of approximate composition Bi94Sb6 were measured within the temperature range 10-300 K. Besides the electrical conductivity and thermoelectric power the magnetoresistance, the Hall effect and the thermoelectric power in a magnetic field were investigated. Measurements in low magnetic fields yield the mobility tensor for Te-doped samples and in connection with the Shubnikov-de Haas oscillations in higher magnetic fields the effective mass tensor of the electrons. Corresponding investigations on Sn-doped p-conducting samples in this paper give the mobility tensors of light and heavy holes and approximately the effective mass tensor. Here quantum oscillations of the thermoelectric power in a magnetic field were analysed.

Oscillatory effective mass in degenerate narrow-gap semiconductors in a quantizing magnetic field

1981 ◽  
Vol 25 (2) ◽  
pp. 105-108 ◽  
Author(s):  
A. N. Chakravarti ◽  
A. K. Chowdhury ◽  
K. P. Ghatak ◽  
S. Ghosh ◽  
A. Dhar
Keyword(s):  
Magnetic Field ◽  
Effective Mass ◽  
Narrow Gap ◽  
Narrow Gap Semiconductors ◽  
Quantizing Magnetic Field
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