Ground State For Hydrogenic Impurity Research Articles

Intense laser field and conduction band-edge nonparabolicity effects on hydrogenic impurity states of InGaN QW

In this paper, hydrogenic impurity ground-state binding energy in unstrained wurtzite (In, Ga)N symmetric quantum well is investigated. The heterostructure is considered under the action of an intense laser field (ILF) incorporating an additional internal probe as well as the conduction band-edge nonparabolicity effect (CBENP). The variational approach is used within the framework of single band effective-mass approximation with two-parametric 1S-hydrogenic trial wavefunction. The competition effect between internal and external perturbations is also shown. Our results reveal that the binding energy is the largest for the well width around the effective Bohr radius and is strongly influenced by both parameters. Moreover, the principle effect of ILF (CBENP) is to reduce (enhance) the binding energy. It is found that the lift of the conduction band-edge can be easily eliminated by adjusting the ILF-parameter.

Effect of electric and magnetic fields on impurity binding energy in zinc-blend symmetric InGaN/GaN multiple quantum dots.

The binding energy of ground state for hydrogenic impurity in multiple quantum dots is calculated in the framework of effective-mass approximation and using a variational method. It is shown that the binding energy is a function of the size of dots, impurity position and external fields strength. The binding energy has a maximum value when the impurity is located on the center of dots and decreases for other impurity positions. The external electric and magnetic fields change the magnitude and the position of peaks. PACS Codes 73.20.D; 71.21.La; 71.55.Eq

Binding energy of hydrogenic impurity in [formula omitted] multi-quantum-dot structure

In this paper, we perform a theoretical study, using a variational method, of the binding energy of ground state for hydrogenic impurity in the multi-quantum-dot structure. It is found that the binding energy is not only as a function of the size of the system in the x – y plane, but also the barrier thickness and the width of a dot in the z direction. Especially, when the barrier thickness is equal to the width of a dot, there are two peaks in the behavior of the binding energy as a function of the barrier thickness. All these behaviors of the binding energy are determined by the competition between the localization effect of the wave function and the tunneling effect of the wave function due to an increase or decrease in the barrier thickness and the width of a dot. Moreover, we also investigate the behavior of binding energy with different impurity position.

Hydrogenic impurity ground state in quantum well: the envelope function revisited

We present a new variationnal method for calculating the ground state energy of an electron bound to an impurity located in a quantum well. This method relies on an envelope function which is determined exactly from a formal minimization procedure. The obtained energies are lower by as much as 10% than the ones found by the widely used free electron envelope function. Their large width limits are reached with exponentially small corrections as they should. We also find that, except for narrow wells, the shape of these exact envelope functions strongly depends on the impurity position, being consequently quite different from the usual free electron ones. In order to discuss the improvements brought by our new procedure in the most striking way, we have used a model semiconductor quantum well with infinite barrier height and simplified band structure. Extensions can be made to finite barrier and more realistic band structures, following the same technique.

The effect of a spatially dependent effective mass on hydrogenic impurity binding energy in a finite parabolic quantum well with a magnetic field

The effect of a spatially dependent effective mass in a finite GaAs/AlxGa1−xAs parabolic quantum well with a magnetic field on hydrogenic impurity ground state (1s) binding energies, and lowly excited state (2p±-like) has been calculated, respectively, as a function of well width and magnetic field and impurity position by using the one-dimensional method. We compare our results with square quantum wells and without the effect of spatially dependent effective mass result. The physical meaning of the wave function square is discussed.

Binding energy of a confined hydrogenic impurity in a semiconductor quantum well.

We have variationally calculated the binding energy of a hydrogenic atom in an infinite semiconductor quantum well with and without an applied electric field along the growth axis. The hydrogenic ground states associated with even-parity excited quantized levels are considered. The binding-energy variation with well width is different for hydrogenic impurity ground state associated with different excited states of the well. The variation of electron energy with applied electric field is also different for different excited quantized levels. The electric-field-induced polarization is quite different for the excited quantized levels. Unlike exciton ground states, the hydrogenic ground states do not appear to be pinned when an electric field is applied.