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Acousto-Electric Interaction in Magnetised Piezoelectric Semiconductor Quantum Plasma

100%
Ghosh S., Muley A.
Acta Physica Polonica A
|
2016
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vol. 130
|
issue 6
1401-1405
EN
Amplification of an acoustic wave is considered in magnetised piezoelectric n-type semiconductor plasma under quantum hydrodynamic regime. The important ingredients of this study are the inclusion of quantum diffraction effect via the Bohm potential, statistical degeneracy pressure, and externally applied magnetostatic field in the momentum balance equation of the charged carriers. A modified dispersion relation is derived for evolution of acoustic wave by employing the linearization technique. Detailed analysis of quantum modified dispersion relation of acoustic wave is presented. For a typical parameter range, relevant to n-InSb at 77 K, it is found that the non-dimensional quantum parameter H reduces the gain while magnetic field enhances the gain of acoustic wave. The crossover from attenuation to amplification occurs at (ϑ₀/ϑₛ)=1 and this crossover point is found to be unaffected by quantum correction and magnetic field. It is also found that the maximum gain point shifts towards lower drift velocity regime due to the presence of magnetic field while quantum parameter H shifts this point towards higher drift velocity. Numerical results on the acoustic gain per radian and acoustic gain per unit length are also illustrated. Our results could be useful in understanding acoustic wave propagation in magnetised piezoelectric semiconductor in quantum regime.
2
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Dispersion and Absorption of Longitudinal Electro-Kinetic Waves in Magnetized Ion-Implanted Semiconductor Plasmas

100%
Ghosh S., Thakur P.
Acta Physica Polonica A
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2007
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vol. 111
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issue 2
247-256
EN
The instability of longitudinal electro-kinetic wave that is propagating across the magnetic field B_0 in ion-implanted group-IV semiconductor sample consisting of non-drifting electrons, holes, and negatively charged colloids is investigated. Using hydrodynamic approach, a compact dispersion relation D(ω,k) is derived for the same. The propagation and amplification characteristics of the wave in collision dominated regime are studied numerically in detail for slow and fast modes. Results show that the presence of transverse magnetic field is responsible for the modification of the existing wave spectra of the slow electro-kinetic branch. In case of fast electro-kinetic wave, the presence of magnetic field is found responsible for excitation and amplification of a new mode. It is also found that the magnetic field is responsible for the conversion of two existing aperiodic modes into periodic ones. These novel periodic modes are found to be counter-propagating in nature.
3
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Phonon-Plasmon Interactions in Inhomogeneous Semiconductor Plasma Embedded with Nanoparticle Cluster

100%
Ghosh S., Dubey P.
Acta Physica Polonica A
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2018
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vol. 133
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issue 5
1287-1293
EN
Phonon-plasmon interaction in inhomogeneous piezosemiconductor embedded with a nanoparticle cluster is examined using hydrodynamic model of plasma and macroscopic model of piezoelectric media. Present work dealt with the extensive investigation of acoustic wave amplification characteristics. The effects of density gradient δ and non-dimensional parameter l related to nanoparticle cluster on acoustic gain have been studied with varying medium electron density n_{0e}, wave frequency ω and velocity ratio ϑ_{0}/ϑ_{s}. The results so obtained, infer that the varying inhomogeneity and presence of nanoparticle cluster within the semiconductor plasma medium play decisive role in depicting the gain characteristics of acoustic wave.
4
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Amplitude Modulation and Demodulation in Strain Dependent Diffusive Semiconductors

100%
Ghosh S., Yadav N.
Acta Physica Polonica A
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2007
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vol. 112
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issue 1
29-40
EN
In communication processes, amplitude modulation is very helpful to save power by using a single band transmission. Thus in this paper authors have explored the possibility of amplitude modulation as well as demodulation of an electromagnetic wave in a transversely magnetized electrostrictive semiconductor. The inclusion of carrier diffusion and phenomenological damping coefficient in the nonlinear laser-semiconductor plasma interaction adds a new dimension to the analysis present in this paper. This problem is analyzed in different wave number regimes over a wide range of cyclotron frequencies. It is found that the complete absorption of the waves takes place in all the possible wavelength regimes when the cyclotron frequency (ω_c) becomes exactly equal to (ν^2+ω_0^2)^{1/2} in absence of damping parameter. It has also been seen that diffusion of charge carriers modifies amplitude modulation and demodulation processes significantly. The damping parameter plays a very important role in deciding the parameter range and selecting the side band mode that will be modulated by the above-mentioned interaction.
5
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Effect of Density Gradient on the Acousto-Electric Wave Instability in Ion-Implanted Semiconductor Plasmas

100%
Ghosh S., Khare P.
Acta Physica Polonica A
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2006
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vol. 109
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issue 2
187-197
EN
Using hydrodynamic model of inhomogeneous plasma, an analytical investigation of excitation of acousto-electric mode was made in n-type piezoelectric ion-implanted semiconductor plasma. By employing the multi-fluid balance equations along with the elastic and Maxwell equations, a compact dispersion relation for the cases in which colloidal grains are either stationary (ϑ_{0d}=0) or streaming (ϑ_{0d}≢0$) is derived. We find that the choice of homogeneous medium is favorable in achieving higher acoustic gain per radian and the results of the investigation should be useful in understanding the characteristics of longitudinal acousto-electric wave in ion-implanted piezoelectric semiconductor whose main constituents are electrons and negatively charged colloidal particles.
6
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Strongly Correlated Electron Behaviour in CeT_2Al_8 (T~=~Fe,~Co)

100%
Ghosh S., Strydom A.
Acta Physica Polonica A
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2012
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vol. 121
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issue 5-6
1082-1084
EN
We report on studies of physical properties of the two compounds CeFe_2Al_8 and CeCo_2Al_8 in which we have found varying degrees of electronic correlational phenomena. No magnetic ordering was detected down to 0.4 K in either of the two compounds. At elevated temperatures an incoherent Kondo interaction between the Ce 4f-electron and the conduction electrons is prevalent in both compounds. CeCo_2Al_8 exhibits a stable 4f-electron magnetic moment, but in CeFe_2Al_8 an intermediate-valent state prevails near room temperature that eventually transforms into a Fermi-liquid ground state. The low-temperature specific heat of CeCo_2Al_8 shows typical strongly correlated electron behaviour and a - logT upturn in its electronic specific heat below about 10 K.
7
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Parametric Amplification in Magnetized Nondegenerate Semiconducting Plasmas

81%
Jat K., Neogi A., Ghosh S.
Acta Physica Polonica A
|
1991
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vol. 79
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issue 6
829-841
EN
Using the straightforward coupled-mode theory, the parametric amplification is analytically investigated in magnetized piezoelectric as well as non-piezoelectric semiconductors. The origin of nonlinear interaction is taken to be in the second-order optical susceptibility χ^{(}2) arising from the nonlinear induced current density. The threshold value of the pump electric field E_{0th} is obtained for crystals. E_{0th} is found to decrease with the rise in magnetic field and fall with the rise in scattering angle. Parametric gain constants are obtained for different situations of practical interest, i.e. (i) for piezoelectric coupling only g_{p}, (ii) for deformation potential coupling only g_{d}, (iii) for both the couplings g_{b}. Numerical investigations reveal that the magnetic field increases the gain. Maximum gains are obtained for backward scattered mode. g_{d} is always found to be less than g_{p} and g_{b}. It is also found that g_{p} and g_{b} both are identical up to k ≈ x 10^{7}m^{-1} and for k ≥ 3 x 10^{7}m^{-1}, g_{b} exceeds g_{p}.
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