Repulsive Impurity Doped Quantum Dot Research Articles

Impurity Modulated Static Linear and First Nonlinear Polarizabilities of Doped Quantum Dots

We explore the pattern of linear and first nonlinear optical (NLO) response of repulsive impurity doped quantum dots harmonically confined in two dimensions. The dopant impurity potential chosen assumes Gaussian form. The quantum dot is subject to a static electric field. For some fixed values of transverse magnetic field strength (ωc), and harmonic confinement potential (ω0), the influence of impurity strength (V0), impurity stretch (ξ), and impurity location (r0) on the diagonal components of static linear (αxx and αyy), and the first NLO (βxxx and βyyy) responses of the dot are computed through linear variational route. The investigation reveals the crucial roles played by the various impurity parameters in modulating these optical responses. Interestingly, maximization in the first NLO responses has been observed for some particular dopant location and at some particular value of spatial stretch of the dopant.

Influence of relative confinement oscillation and concomitant oscillatory impurity domain on excitation profile of doped quantum dots

We investigate the excitation behavior of a repulsive impurity doped quantum dot under the combined influence of oscillatory confinement potential and oscillatory magnetic field. In view of this the ratio of two oscillation frequencies has been exploited meticulously. We have considered Gaussian impurity centers. The investigation reveals that a variation in the aforesaid frequency ratio causes maximization in the time-average excitation rate for different dopant locations. To make the analysis more realistic and rational, concomitant oscillation in the spatial stretch of the dopant is also considered in a stepwise manner. Although the consideration makes the calculation much more tedious and involved, yet this adequately describes the role played by the undulating impurity domain exclusively in modulating the excitation rate.

The randomly fluctuating impurity strength initiated excitation in doped quantum dots

We investigate the excitation behavior of a repulsive impurity doped quantum dot under the influence of randomly fluctuating dopant potential. We have considered Gaussian impurity centers doped at different locations. The investigation reveals the interplay between dopant location and dopant’s spatial stretch in modulating the excitation pattern. Maximization in the excitation rate has been observed as a function of fluctuating dopant strength owing to the conflict between opposing influences that promote and hinder excitation.

Excitations in doped quantum dot insisted by discontinuous reversals of static electric field: Interplay between pulse and dopant site

We explore the excitation profile of a repulsive impurity doped quantum dot. The quantum dot is subject to a discontinuously reversing static electric field. The dopant impurity potential chosen assumes Gaussian form. The investigation reveals the key role played by the dopant location and the number of pulses offered by the external field to the dot in controlling the excitation rate. Time-dependent Hellman–Feynman theorem has been invoked to understand the extent of energy transfer between field direction and the direction where no field is applied. The combined transition rate from ground to other excited states is also determined to support the findings.

Excitations in doped quantum dot induced by accelerating impurity center

We explore the excitation profile of a repulsive impurity doped quantum dot induced by drift of accelerating dopant. The acceleration begins as the velocity of the drifting dopant changes randomly with time. We have considered Gaussian impurity centers. The investigation reveals the roles subtly played by the region of influence of the dopant in conjunction with the dopant strength to modulate the excitation pattern. The investigation also reveals a change in the relative dominance of various factors in influencing the excitation rate as dopant strength increases. The findings seem to be important in the field of impurity diffusion in nanodevices.

Impurity controlled excitations in doped quantum dot exposed to periodic external perturbation

We investigate the excitation behavior of a repulsive impurity doped quantum dot under the influence of an oscillatory external electric field. We have considered Gaussian impurity centers doped at on-center position. The investigation reveals that a variation in the strength and spatial stretch of the dopant causes maximization and minimization in the average excitation rate, respectively. The findings are expected to have important applications involving quantum dot nanodevices.

Excitations in doped quantum dot driven by linear and non-linear drift of impurity

We explore the excitation profile of a repulsive impurity doped quantum dot induced by linear and non-linear drift of the dopant location. We have considered Gaussian impurity centers. The investigation reveals the roles subtly played by the region of influence of the dopant in conjunction with the mode of dopant propagation to modulate the excitation pattern. The investigation also reveals a change in the relative dominance of various factors in influencing the excitation rate associated with a change in the mode of dopant shift.

Excitations in doped quantum dot driven by periodically fluctuating impurity domain

We explore the excitation profile of a repulsive impurity doped quantum dot induced by a periodically fluctuating impurity domain. We have considered Gaussian impurity centers. The investigation reveals the effects of the dopant coordinate and dopant strength in conjunction with the oscillating impurity domain to modulate the excitation pattern. The investigation also reveals the maximization in the excitation rate for some typical range of values of dopant location and dopant strength.

Excitations in doped quantum dot insisted by time-dependent sluggish enhancement in dot-impurity overlap

We explore the excitation profile of a repulsive impurity doped quantum dot induced by changing impurity domain that increases slowly with time. We have considered G aussian impurity centers. The investigation reveals the roles delicately played by the dopant coordinate and initial spatial stretch of the dopant to modulate the excitation pattern. The investigation also reveals maximization in the excitation rate for some typical range of values of the said initial spread of dopant regime. A gradual condensation of initial spread of the dopant regularizes the average excitation rate.

Excitations in doped quantum dot induced by randomly fluctuating confinement potential: Influence of impurity

We explore the excitation profile of a repulsive impurity doped quantum dot. The dopant impurity potential chosen assumes Gaussian form. The quantum dot is subject to a randomly fluctuating confinement potential. The investigation reveals the interplay between the impurity strength, impurity location, and impurity domain to modulate the excitation rate. Owing to the interplay we encounter enhancement as well as depletion in the excitation rate as several impurity parameters are varied over a range. Phase space contours are often invoked to rationalize the findings.

Impurity strength and impurity domain modulated frequency‐dependent linear and second non‐linear response properties of doped quantum dots

AbstractWe explore the pattern of frequency‐dependent linear and second non‐linear optical responses of repulsive impurity doped quantum dots harmonically confined in two dimensions. The dopant impurity potential chosen assumes a Gaussian form and it is doped into an on‐center location. The quantum dot is subject to a periodically oscillating external electric field. For some fixed values of transverse magnetic field strength (ωc) and harmonic confinement potential (ω0), the influence of impurity strength (V0) and impurity domain (ξ) on the diagonal components of the frequency‐dependent linear (αxx and αyy) and second non‐linear (γxxxx and γyyyy) responses of the dot are computed through a linear variational route. The investigations reveal that the optical responses undergo enhancement with increase in both V0 and ξ values. However, in the limitingly small dopant strength regime one observes a drop in the optical responses with increase in V0. A time‐average rate of energy transfer to the system is often invoked to support the findings.

Excitations in doped quantum dot induced by randomly fluctuating magnetic field: influence of impurity

We explore the excitation profile of a repulsive impurity doped quantum dot under randomly fluctuating magnetic field. We have considered Gaussian impurity centers. The investigation reveals the roles subtly played by the dopant coordinate, dopant strength, and the region of influence of the dopant to modulate the excitation pattern. The rate of transition to the excited states has been invoked to analyze the roles played by the above impurity parameters in influencing the excitation process. Quantum phase space plots are often exploited to support the findings.

Impurity modulated excitation profile of doped quantum dot subject to oscillatory magnetic field

We explore the excitation profile of a repulsive impurity doped quantum dot under periodically fluctuating magnetic field. We have considered Gaussian impurity centers. The investigation reveals the roles subtly played by the dopant coordinate and the region of influence of the dopant to modulate the excitation pattern. The rate of transition to the excited states has been invoked to analyze the interplay between the above two impurity parameters in influencing the excitation process. The ratio of cyclotron frequency and harmonic confinement potential has important impact on excitation rate.

Role of impurity influenced domain on excitation profile of doped quantum dot subject to oscillatory confinement potential

We explore the excitation profile of a repulsive impurity doped quantum dot under a periodically fluctuating confinement potential. We have considered Gaussian impurity centers. The investigation points to a minimum value of spatial extension of impurity domain below which significant excitation is not feasible. In general, excitation becomes maximum at some typical value of impurity strength depending upon the location and the spatial stretch of the dopant. The rate of transition to the excited states depends on the above spatial stretch which gets modulated by the oscillating confinement potential and explains the excitation maximization quite elegantly.

Effect of impurity strength and impurity domain on excitation of doped quantum dot induced by discontinuously reversing pulsed field

We explore the excitation profile of a repulsive impurity doped quantum dot. The quantum dot is subject to a discontinuously reversing static electric field. The dopant impurity potential chosen assumes Gaussian form. The investigation reveals how impurity strength and impurity domain can influence the excitation rate in conjunction with the number of pulses offered by the external field. Time-dependent Hellmann–Feynman theorem has been invoked to understand the extent of external field-to-dot energy transfer.

Excitations in doped quantum dot driven by discontinuously and randomly reversing electric field: Influence of impurity

We explore the excitation profile of a repulsive impurity doped quantum dot. The dopant impurity potential chosen assumes Gaussian form. The quantum dot is subject to a discontinuously and randomly reversing static electric field. The investigation reveals how impurity strength, impurity location, and impurity domain can influence the excitation rate when the maximum value of randomly varying field reversal time is kept above a threshold value. Time-dependent Hellman–Feynman theorem has been invoked to understand the extent of external field-to-dot energy transfer.

Dynamics of electron impurity doped quantum dots in the presence of time-varying fields: Influence of impurity location

We explore the pattern of time evolution of eigenstates of a repulsive impurity doped quantum dot. The quantum dot is two dimensional and contains one electron which is harmonically confined. We have considered Gaussian impurity centers. A static transverse magnetic field is also present. For given strength of confining fields, intensity and oscillation frequency of external time-varying field, the system reveals a long time dynamics that is undulatory in nature. The location of impurity at on and off-center positions prominently affects the eigenstates of the unperturbed system and consequently the nature of the dynamics. Separations between various energy levels and corresponding transition moment values as a function of impurity position are invoked to explain the dynamical features. The Fourier transform of time evolution profiles indicates the role of collective excitations towards population build up in some particular states.

Repulsive impurity doped quantum dot subjected to oscillatory confinement potential: Role of dopant strength and dopant location on time-evolution

We explore the pattern of time evolution of eigenstates of a repulsive impurity doped quantum dot. The quantum dot is 2-dimensional and contains one electron which is harmonically confined. We have considered Gaussian impurity centers. A static transverse magnetic field is also present. Under a periodically fluctuating confinement potential, the system reveals a long time dynamics. The investigation points to a typical value of impurity potential strength at which the excitation is maximum. This typical value has also been found to be strongly dependent on dopant location. The rate of transition between the eigenstates depends delicately on several impurity dependent factors modulated by the oscillating confinement potential and explains the excitation maximization quite elegantly.

Oscillatory impurity potential induced dynamics of doped quantum dots: Analysis based on coupled influence of impurity coordinate and impurity influenced domain

We explore the pattern of time evolution of eigenstates of a repulsive impurity doped quantum dot. The quantum dot is 2-dimensional and contains one electron which is harmonically confined. We have considered Gaussian impurity centers. A static transverse magnetic field is also present. Under a periodically fluctuating impurity potential, the system reveals a long time dynamics that is undulatory in nature. Coupled to the dopant location, the domain of influence of the impurity potential affects the separation between the eigenstates of the unperturbed system. The investigation points to a threshold value of spatial extension of impurity potential. Above this threshold value, the dopant location becomes important in monitoring the minimum value of impurity potential required to cause excitation.