Two-dimensional Quantum Pseudodot System Research Articles

The ground-state lifetime of polaron in a two-dimensional quantum pseudodot system

We study the ground-state lifetime (GSL) of polaron in a two-dimensional RbCl quantum pseudodot (QPD) system by using a variational method of Pekar type (PTVM) and the quantum statistical theory. Considering the polaron effect, we derive the dependent relations of the temperature, the electric field, the chemical potential (CP) of the two-dimensional electron gas (TDEG), the polaron radius (PR) and the zero point (ZP) of the pseudoharmonic potential (PHP) on the GSL of polaron. The calculated results show that the GSL $$\tau$$ of polaron will decrease when the CP $$V_{0}$$ of the TDEG, the electric field and the PR $$R_{p}$$ increase, but will increase while the ZP $$r_{0}$$ of the PHP, the ground-state energy (GSE) and the temperature parameter $$\gamma$$ become larger, respectively. That means that by changing the electric field, the temperature, the PR, the CP of the TDEG and the ZP of the PHP, one can adjust the GSL of polaron, which may offer new insight into studying many related applications in quantum computation (QC) and control of electron transition.

One-phonon Raman scattering in a two-dimensional quantum pseudo-dot system

We present theoretical results concerning the electron Raman scattering process related to the longitudinal optical (LO) phonon modes in a two - dimensional quantum pseudo - dot, under the influence of a uniform magnetic field. The Fröhlich electron - phonon interaction for resonance Raman scattering is considered. External magnetic field, the geometrical size of the pseudo - dot and the electron - phonon interaction effects on the differential cross - section of the Raman scattering are investigated. Our Results reveal that the geometrical parameters of the pseudo - dot as well as the external magnetic field and electron - phonon interaction have a great influence on the position and the magnitude of the peaks of the emission spectra.

Intense laser field effects on the third-harmonic generation in a quantum pseudodot system

In this research, we present the effects of high-frequency intense laser field on the third-harmonic generation associated with intersubband transitions in a two-dimensional quantum pseudodot system subjected to an uniform external magnetic field. Non-resonant monochromatic laser radiation with circular polarization is considered within the framework of high-frequency Floquet approach. On the basis of the compact-density matrix approach and an iterative method, the third-harmonic generation coefficient is calculated. The results presented for a GaAs quantum dot show that: (i) the position and magnitude of the resonant peak of third-harmonic generation depend strongly on magnetic field, the chemical potential and zero-point of pseudoharmonic potential; (ii) the strength of intense laser field modifies the confinement potential which results in considerable changes in the nonlinear optical response of the system.

Laser-induced nonlinear optical rectification in a two-dimensional quantum pseudodot system

In this work, the effects of intense laser field on the nonlinear optical rectification in a two-dimensional quantum pseudodot system subjected to an uniform external magnetic field have been investigated theoretically. The non-resonant monochromatic intense laser field with circular polarization has been taken into account within the framework of high-frequency Floquet theory. Analytical expression for the coefficient of nonlinear optical rectification is deduced by using the compact-density matrix approach and iterative method. Numerical results show that the nonlinear optical rectification coefficient depends strongly on the magnitude of magnetic field, the chemical potential and zero point of the pseudoharmonic potential. Moreover, we have demonstrated that the strength of intense laser field alters the structure of confinement potential and affects remarkably the nonlinear optical rectification coefficients.

Optical response in a laser-driven quantum pseudodot system

We investigate theoretically the intense laser-induced optical absorption coefficients and refractive index changes in a two-dimensional quantum pseudodot system under an uniform magnetic field. The effects of non-resonant, monochromatic intense laser field upon the system are treated within the framework of high-frequency Floquet approach in which the system is supposed to be governed by a laser-dressed potential. Linear and nonlinear absorption coefficients and relative changes in the refractive index are obtained by means of the compact-density matrix approach and iterative method. The results of numerical calculations for a typical GaAs quantum dot reveal that the optical response depends strongly on the magnitude of external magnetic field and characteristic parameters of the confinement potential. Moreover, we have demonstrated that the intense laser field modifies the confinement and thereby causes remarkable changes in the linear and nonlinear optical properties of the system.

The Rashba and Dresselhaus spin-orbit interactions in a two-dimensional quantum pseudo-dot system

We study the impact of the spin-orbit coupling due to both structure and crystal inversion asymmetry and external magnetic field on the level structure in a two-dimensional quantum pseudo-dot. It is demonstrated that, both the spin-orbit interactions and magnetic field strength have a great influence on energy eigenvalues of the system. Also, we found that an increase in magnetic field enhances the spin-orbit coupling strength. This phenomena leads to increase the energy eigenvalues and energy splitting due to the spin-orbit coupling.

Electromagnetically induced transparency in a two-dimensional quantum pseudo-dot system: Effects of geometrical size and external magnetic field

Electromagnetically induced transparency in a two-dimensional quantum pseudo-dot system, under the influence of a uniform magnetic field, is theoretically investigated. In this regard, the effects of external magnetic field and the geometrical size of the pseudo-dot system on the absorption as well as refractive index and the group velocity of the probe light pulse are investigated. The results show that the electromagnetically induced transparency occurs in the system and its frequency, transparency window and group velocity of the probe field are affected by the external magnetic field and the geometrical size of the pseudo-dot system. Also, electromagnetically induced transparency and the group velocity of light can be controlled via the external magnetic field and geometrical size.

Polaron effects on the optical rectification in a two-dimensional quantum pseudodot system

Using the compact density-matrix approach and the iterative method, the optical rectification in a two-dimensional quantum pseudodot system under the influence of a static magnetic field is theoretically investigated. The effects of an external magnetic field and the geometrical size of the pseudodot system on the optical rectification are presented. What’s more, we find that the polaron effect has an important influence on the optical rectification.

Polaron effects on the third-harmonic generations in a two-dimensional quantum pseudodot system

The third-harmonic generations (THG) considering polaron effects in the two-dimensional quantum pseudodot system with a uniform magnetic field are theoretically studied. It is found that the THG coefficient is strongly affected not only by an external magnetic field, but also by the geometrical size of the pseudodot system. Moreover, the theoretical values of the THG is obviously increased when considering the electron–LO–phonon interaction.

Electron Raman scattering of a two-dimensional pseudodot system

We have carried out the theoretical investigation of the differential cross section for the electron Raman scattering process, which is associated with intersubband transitions in a two-dimensional quantum pseudodot system. The great advantage of our methodology is that it enables confinement regimes by varying two parameters in the model potential. It is found that the differential cross section is affected by the external magnetic field, the geometrical size and the chemical potential of the pseudodot system.

Polaron effects on the optical absorption coefficients and refractive index changes in a two-dimensional quantum pseudodot system

The linear and nonlinear optical absorption coefficients (ACs) and refractive index (RI) changes are obtained by using a compact density matrix approach and an iterative procedure. With typical semiconducting GaAs materials, the linear, third-order nonlinear, total optical absorption coefficients and the optical refractive index have been examined. We find that the polaron effect has an important influence on the linear and nonlinear optical properties.

Third-harmonic generation in two-dimensional pseudo-dot system with an applied magnetic field

Third-harmonic generation (THG) in a two-dimensional quantum pseudo-dot system with an applied magnetic field is theoretically investigated. THG coefficient is obtained by using the compact-density matrix approach and an iterative method. Numerical results are presented for typical GaAs/AlGaAs pseudo-parabolic quantum dots. The results show that the external magnetic field and the geometrical size of the pseudo-dot system have evidently influences on the THG, whereas their influences are different.

Optical rectification coefficient of a two-dimensional quantum pseudodot system

Optical rectification coefficient associated with intersubband transitions in a two-dimensional quantum pseudodot system, under the influence of an uniform magnetic field is theoretically investigated. In this regard, the compact-density matrix approach and an iterative method are used to find the optical rectification coefficient of the pseudodot system. We have investigated the effects of an external magnetic field, the geometrical size and the chemical potential of the pseudodot system on this coefficient. It is found that optical rectification coefficient is affected by the external magnetic field, the geometrical size and the chemical potential of the pseudodot system.

Intersubband optical absorption coefficient changes and refractive index changes in a two-dimensional quantum pseudodot system

The optical absorption coefficient changes and refractive index changes associated with intersubband transitions in a two-dimensional quantum pseudodot system under the influence of a uniform magnetic field are theoretically investigated. In this regard, the electronic structure of the pseudodot system is studied using the one-band effective mass theory, and by means of the compact density matrix approach linear and nonlinear optical absorption coefficient and refractive index changes are calculated. The effects of an external magnetic field and the geometrical size of the pseudodot system on the optical absorption coefficient and refractive index changes are investigated. It is found that the absorption coefficient and refractive index changes are strongly affected not only by an external magnetic field but also by the geometrical size of the pseudodot system.