Quasi-stationary Electron States Research Articles

Properties of spectral characteristics of quasi-stationary electron states in an open multi-cascade nanostructure

The exact expressions for scattering matrix and transmission coefficient in open multi-cascade nanostructure are obtained. The theory of spectral characteristics of electron quasi-stationary states is developed in two approaches. For the nanostructure with GaAs wells and AlGaAs barriers, it is established that resonance bands appear in the N-cascade structure. Each one is formed by the energies of N states. Only the scattering matrix allows to unambiguously determine the resonance energies and resonance widths of all electron states in the multi-cascade structure. The approach of transmission coefficient, due to the collapse of resonances, gives the incomplete information about the spectral characteristics.

Optically induced resonant tunneling of electrons in nanostructures

We developed the theory of elastic electron tunneling through a potential barrier driven by a strong high-frequency electromagnetic field. It is demonstrated that the driven barrier can be considered as a stationary two-barrier potential which contains the quasi-stationary electron states confined between these two barriers. When the energy of an incident electron coincides with the energy of the quasi-stationary state, the driven barrier becomes fully transparent for the electron (the resonant tunneling). The developed theory is applied to describe electron transport through a quantum point contact irradiated by an electromagnetic wave.

Quasi-stationary electron states in a multilayered structure in longitudinal electric and transverse magnetic fields

A theory of spectral parameters, dynamic conductivity, and relative integrated emission intensity has been proposed in the model of the open resonant-tunneling structure as a separate cascade of a quantum cascade laser in a transverse magnetic field. It has been shown that, according to the experiment by Blaser and colleagues, as the magnetic field strength increases to 8 T, the emission peak shifts to higher energies, while its relative integrated intensity in the strength range of 0–14 T decreases abruptly.

Quasi-stationary states of electrons interacting with strong electromagnetic field in two-barrier resonance tunnel nano-structure

An exact solution of non-stationary Schrodinger equation is obtained for a one-dimensional movement of electrons in an electromagnetic field with arbitrary intensity and frequency. Using it, the permeability coefficient is calculated for a two-barrier resonance tunnel nano-structure placed into a high-frequency electromagnetic field. It is shown that a nano-structure contains quasi-stationary states the spectrum of which consists of the main and satellite energies. The properties of resonance and non-resonance channels of permeability are displayed.

Calculations of the equation of state by the Liberman mode

The algorithm of the calculation of self-consistent atomic potential accounting for resonant states of electrons is developed by the Liberman model. The resonant states are related to quasi-stationary states of electrons and appear at the squeezing of bound levels of energy into continuum accompanied by an increase in the density of a substance. Such states play an important role in calculations of thermodynamic functions of substance, since they facilitate the smooth dependences of pressure and internal energy on density. Appropriate software (RESEOS) was developed and calculations of the equations of state of aluminum and uranium were performed in a wide range of temperatures and densities. The resulted shock adiabats were compared with the experimental data.

Theory for the optimal geometric design of a two-barrier nano detector working at the quantum transitions between two lowest quasi-stationary electron states

Theory for the optimal geometric design of a two-barrier nano detector working at the quantum transitions between two lowest quasi-stationary electron states

Quasistationary Electron States for CdTe/ZnTe/CdTe Open Spherical Quantum Dots

The energy spectra of an electron in open spherical quantum dot (QD) within the effective mass approximation (EMA) and rectangular potential model is presented. Energy structure of quantum dots is important because of their possible applications in electronic and optoelectronic devices. For proper description and interpretation of tunneling processes knowledge of resonant states of quantum dots is necessary. Energy values depend on parameter like size of system and spatial composition. The lifetimes of the quasistationary states are computed within the framework of the scattering S-matrix method. It is shown how core radius and barrier thickness for the CdTe/ZnTe/CdTe example influence electron states and their lifetimes.

Plane two-barrier resonance-tunneling structures: Resonance energies and resonance widths of quasi-stationary electron states

A theory of resonance energies and widths of quasi-stationary states is suggested; this theory is based on the distribution function of the probability density for the location of an electron in a two-barrier resonance-tunneling structure, and on the use of a transfer matrix and an S scattering matrix in the models of rectangular and δ-shaped potentials with various effective masses in the layers of the nanosystem. With an In0.53Ga0.47As/In0.52Al0.48As nanosystem as an example, the evolution of spectral parameters of an electron’s quasi-stationary states is analyzed in relation to geometric sizes of the resonance-tunneling structure; these states were calculated using three different methods. It is shown that, since the δ-barrier model overestimates the resonance width by several tens of times in comparison with a more realistic model of rectangular potentials, the former model can be only used for rough estimations.

The lack of the stabilization of quasi-stationary electron states in a strong magnetic field

The lack of the stabilization of quasi-stationary electron states in a strong magnetic field

Quasi-stationary states of electrons and holes in an open composite cylindrical quantum wire

The energies of the quasi-stationary states of electrons and holes in an open composite cylindrical quantum wire are calculated within the effective-mass approximation by means of the S-matrix theory. Specific calculation is carried out for the HgS/CdS/HgS system. The poles of the S matrix in the complex energy plane are studied. The dependences of the lifetimes of quasiparticles in quasi-stationary resonance states on the longitudinal quasi-momentum and geometric parameters of the nanosystem are obtained. It is shown that the quasiparticle lifetimes in the resonance states exponentially diminish as the longitudinal quasi-momentum increases.