On the photoconductivity of hot electrons in semiconductors at low temperatures

1983 ◽  
Vol 61 (6) ◽  
pp. 821-824
Author(s):  
E. F. El-Wahidy
Keyword(s):  
Low Temperatures ◽  
Theoretical Study ◽  
Zero Point ◽  
Potential Scattering ◽  
Hot Electrons ◽  
Average Lifetime ◽  
Deformation Potential ◽  
Acoustic Phonons ◽  
Temperature Dependences ◽  
Point Lattice

A theoretical study is made of the photoconductivity of hot photoelectrons interacting with acoustic phonons in n-type germanium at low temperature, T = 4 K, when the equipartition of the energy of phonons is not obeyed. Assuming that the energy relaxation of photoelectrons takes place by the spontaneous emission of acoustic phonons, the energy distribution of photoelectrons is obtained using the deformation potential scattering by acoustic phonons for the zero point lattice. The distribution function is then used in calculating the photoconductivity and average lifetime of photoelectrons. New temperature dependences of the photoconductivity and average lifetime arc obtained. It is shown that the new results differ from those reported when equipartition is obeyed.

scholarly journals Theoretical study of transition radiation from hot electrons generated in the laser–solid interaction

2003 ◽  
Vol 10 (7) ◽  
pp. 2994-3003 ◽  
Author(s):  
Jian Zheng ◽  
K. A. Tanaka ◽  
T. Miyakoshi ◽  
Y. Kitagawa ◽  
R. Kodama ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Transition Radiation ◽  
Hot Electrons

THEORY OF THE INTERACTION BETWEEN THE LATTICE VIBRATIONS AND THE ROTATIONAL MOTION IN SOLID HYDROGEN

1966 ◽  
Vol 44 (2) ◽  
pp. 313-335 ◽  
Author(s):  
J. Van Kranendonk ◽  
V. F. Sears
Keyword(s):  
Rotational Motion ◽  
Zero Point ◽  
Solid Hydrogen ◽  
The Self ◽  
Intermolecular Potential ◽  
Lattice Vibrations ◽  
Energy Effect ◽  
Self Energy ◽  
Blowing Up ◽  
Point Lattice

The effects of the interaction between the rotational motion of the molecules in solid hydrogen and the lattice vibrations, resulting from the anisotropic van der Waals forces, have been investigated theoretically. For the radial part of the anisotropic intermolecular potential an exp–6 model has been adopted. First, the effect of the lattice vibrations, and of the anistropic blowing up of the crystal by the zero-point lattice vibrations, is discussed. The effective anisotropic interaction resulting from averaging the instantaneous interaction over the lattice vibrations is calculated by assuming a Gaussian distribution for the modulation of the relative intermolecular separations by the lattice vibrations. Secondly, the displacement of the rotational levels due to the self-energy of the molecules in the lattice is calculated both classically and quantum mechanically, and the resulting shifts in the frequencies of the rotational transitions in solid hydrogen are given. Finally, the splitting of the rotational levels due to the anisotropy of the self-energy effect is calculated. The theory is applied to the calculation of the asymmetry of the S0(0) triplet in the rotational Raman spectrum of solid parahydrogen, and of the specific heat anomaly in solid hydrogen at low ortho-concentrations.

A Theoretical Study on the Pressure Dependence of the Band Gap in ${\rm A^{I}B^{III}C^{VI}_2}$ Compounds

1997 ◽  
Vol 11 (16) ◽  
pp. 1959-1967 ◽  
Author(s):  
R. Asokamani ◽  
R. Mercy Amirthakumari ◽  
G. Pari
Keyword(s):  
Theoretical Study ◽  
Energy Gap ◽  
Ambient Pressure ◽  
Chalcopyrite Structure ◽  
Deformation Potential ◽  
Equilibrium Lattice Constant ◽  
Self Consistent ◽  
Direct Energy ◽  
Experimental Values ◽  
Direct Energy Gap

The self-consistent scalar relativistic band structure for AgGaX 2 (X = S, Se, Te) performed in chalcopyrite structure using the TBLMTO method at various pressures are reported here. Empty spheres were introduced in the calculations as the chalcopyrite structure is loosely packed. From the total energy calculations, the equilibrium lattice constant and the bulk modulus at zero pressure were calculated and these values agree well with the reported experimental values. All these compounds are found to have direct energy gap at ambient pressure with the gap widening with increased pressures which are in agreement with the experimental results. The deformation potential, dE g /dP for the compounds are also reported here. The metallisation volumes are calculated and the possibility of observing superconductivity in these compounds is discussed.

Impact of deformation potential scattering on free-carrier induced optical nonlinearities: An experimental study in GaAs

2002 ◽  
Vol 91 (7) ◽  
pp. 3992-3999 ◽  
Author(s):  
V. Kotov ◽  
J. Stiens ◽  
G. Shkerdin ◽  
W. Ranson ◽  
C. De Tandt ◽  
...  
Keyword(s):  
Experimental Study ◽  
Potential Scattering ◽  
Free Carrier ◽  
Optical Nonlinearities ◽  
Deformation Potential

scholarly journals A theoretical study of a possible model of paramagnetic alums at low temperatures

1940 ◽  
Vol 176 (965) ◽  
pp. 203-213 ◽  
Keyword(s):  
Magnetic Field ◽  
Low Temperatures ◽  
Theoretical Study ◽  
Spontaneous Magnetization ◽  
Critical Value ◽  
Transition Curve ◽  
Thin Specimen ◽  
First Order ◽  
Freely Suspended ◽  
Line Of Critical Points

An attempt is made to examine theoretically the properties of paramagnetic alums at low temperatures. The model taken is a lattice of freely suspended magnets, all interactions except purely magnetic being neglected. Even with this simplification it is impossible at present to make rigorous calculations of the partition function, either on classical or quantum lines. A simple model is proposed, which is really a generalization of the Bragg - Williams theory enabling one to take account of the effect of a magnetic field. The few configurations whose energies are known are used to fix arbitrary constants in the expression assumed for the energy. The theory predicts that the state of lowest energy is either a spontaneously magnetized, state for a long thin specimen, or a state in which alternate rows of magnets point in opposite directions for a sphere, spontaneous magnetization appearing in an ellipsoid with an eccentricity greater than a certain critical value. The transition curve bounding the region in which the antiparallel state is stable consists partly of a line of Curie points corresponding to transitions of the second, order, passing smoothly into a line of critical points corresponding to a transition of the first order. The effect of shape on the magnetic properties of the specimen seems to be experimentally verified, but the rough nature of the theory prevents it being more than qualitative.

Anomaly of Nuclear Quadrupole Relaxation in Cu2O Prepared at Low Temperatures

1986 ◽  
Vol 41 (1-2) ◽  
pp. 382-385 ◽  
Author(s):  
J. Kasprzak ◽  
J. Lus ◽  
J. Pietrzak
Keyword(s):  
Temperature Dependence ◽  
Cuprous Oxide ◽  
Thermal Processing ◽  
Low Temperatures ◽  
Room Temperature ◽  
Quadrupole Relaxation ◽  
Temperature Dependences ◽  
Powder Samples ◽  
Nuclear Quadrupole ◽  
Nuclear Quadrupole Relaxation

The 63Cu and 65Cu NQR transitions in powder samples of cuprous oxide have been investigated from 77 to 500 K and at room temperature after annealing up to 1100 K Significant differences in T1 , NQR linewidth Δv, and their temperature dependences were found among the samples prepared in different ways. For C u20 samples obtained in low temperatures (below 380 K), the temperature dependence of T1 below 380 K is o f activation character with Ea = 0.07 eV. These results are interpreted in terms of an electron hopping mechanism. Thermal processing of these samples permits to obtain irreversible electronic state and then the spectroscopic parameters are the same as for the samples obtained in high temperatures (above 1320 K).

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