Study of Two-Mode Squeezed Magnetopolarons

In this paper, we conduct an investigation into two-dimensional squeezed magnetopolarons. The Hamiltonian of magnetopolarons is dealt with two-mode squeezed states transformation, which is based on the Lee-Low-Pines and Huybrechts （LLP-H） canonical transformations. This method makes it possible to take account of the linear terms, bilinear ones of phonon operators, and the correlation between two longitudinal optical （LO） phonon modes. The energies of the ground state and excited states are evaluated by variational approach, and accurate results are obtained. Furthermore, the renormalized cyclotron masses for some possible transitions are discussed in detail.

Theory of Triple Magnetopolarons in Quantum-Dimensional Nanostructures

A theory of triple magnetopolarons in an isolated quantum well in a strong magnetic field was developed. We study the behavior of the magnetooptical absorption peaks corresponding to the transitions of an electron at the Landau level with quantum numbers n ≥ 2. For n = 2 at the point of equality of cyclotron frequency and the frequency of optical phonon (LO), there is a cross of three terms of the electron-phonon system (the electron at the Landau level n = 2, the electron at n = 1, and the optical phonon and electron at n = 0 and two phonons), considered as a function of the cyclotron frequency. Interaction with phonons takes off the degeneracy of the terms and leads to three disjoint branches of the electron-phonon spectrum. The theory predicts that in the resonant magnetic field, the peak of magnetooptical absorption splits into three peaks, the intensity and position of which are dependent in a complex way on the magnitude of the magnetic field and the constant of the electron-phonon coupling.

Built-in electric field effect on cyclotron mass of magnetopolarons in a wurtzite In_xGa_(1-x)N/GaN quantum well

The cyclotron mass of magnetopolarons in wurtzite InxGa1-xN/GaN quantum well is studied in the presence of an external magnetic field by using the Larsen perturbation method. The effects of the built-in electric field and different phonon modes including interface, confined and half-space phonon modes are considered in our calculation. The results for a zinc-blende quantum well are also given for comparison. It is found that the main contribution to the transition energy comes from half-space and interface phonon modes when the well width is very small while the confined modes play a more important role in a wider well due to the location of the electron wave function. As the well width increases, the cyclotron mass of magnetopolarons first increases to a maximum and then decreases either with or without the built-in electric field in the wurtzite structure and the built-in electric field slightly reduces the cyclotron mass. The variation of cyclotron mass in a zinc-blende structure is similar to that in a wurtzite structure. With the increase of external magnetic field, the cyclotron mass of polarons almost linearly increases. The cyclotron frequency of magnetopolarons is also discussed.

Bose–Einstein distribution temperature features of quasiparticles around magnetopolaron in Gaussian quantum wells of alkali halogen ions

We have applied strong coupling unitary transformation method combined with Bose–Einstein statistical law to investigate magnetopolaron energy level temperature effects in halogen ion crystal quantum wells.The obtained results showed that under magnetic field effect,magnetopolaron quasiparticle was formed through the interaction of electrons and surrounding phonons.At the same time,magnetopolaron was influenced by phonon temperature statistical law and important energy level shifts down and binding energy increases.This revealed that lattice temperature and magnetic field could easily affect magnetopolaron and the above results could play key roles in exploring thermoelectric conversion and conductivity of crystal materials.

Influence of the Electric Field on the Properties of the Bound Magnetopolaron in GaAs Semiconductor Quantum Wells

The influence of the electric field on the properties of the bound magnetopolaron in an infinite-depth GaAs semiconductor quantum well is investigated using the linear-combination operator and the unitary transformation method. The relationships between the polaron＇s ground state energy and the Coulomb bound potential, electric field, magnetic field, and well-width are derived and discussed. Our numerical results show that the absolute value of the polaron＇s ground state energy increases as the electric field and the Coulomb bound potential increase, and decreases as the well-width and the magnetic field strength increase. When the well-width is small,the quantum size effect is significant.

Energy Levels of Strong Coupling Magnetopolaron in Quantum Dot

By using variational method of Pekar type, we have studied the energy levels of strong coupling magnetopolaron in disk shape quantum dot(QD) and quantum well(QW). Our results show that, with the increasing magnetic field and confinement strength, the magnetopolaron binding energy of QD and QW in the ground state and in the excited state is enhanced. The limiting results of bulk type and strict two dimensional type are obtained.

ENERGY LEVELS OF STRONG COUPLING MAGNETOPOLARON IN QUANTUM WIRE

With the use of variational method of Pekar type, this paper studied the energy levels of magnetopolaron in quantum wire with strong electron phonon interaction. The magnetopolaron binding energy in the ground state and in the excited state, as well as the resonance frequency of magnetopolaron were calculated. Their dependence on the cyclotron frequency and the confinement strength of quantum wire was depicted. The limiting case of bulk type and strict two dimensional type was discussed.

Size and Magnetic Field Dependence of Strong Coupling Magnetopolaron in Quantum Dot

By using the variational method of Pekar type, the ground state and the first excited state of the strong coupling magnetopolaron in cylinder shape quantum dot are considered. The results show that, with the increasing cyclotron frequency and the confinement strength, the magnetopolaron binding energies in both the ground state and the excited state, and the resonance frequency of magnetopolaron are enhanced. The limiting case of the bulk and strict one dimensional type is also discussed.

MAGNETIC FIELD AND TEMPERATURE DEPENDENCE OF THE PROPERTIES OF A MAGNETOPOLARON

Taking into account the interaction of an electron with both bulk longitudinaloptical (LO) and interfaceoptical(IO) phonons, we investigate the magnetic field and temperature dependence of the properties of a magnetopolaron at the interface of polarpolar crystals in an external magnetic field by using the generalized Haga perturbation method. The results reveal that as the magnetic field B is lower than critical strengths BCL and BCI, the selftrapping of the interface magnetopolaron weakens with increasing temperature, but it strengthens with the rising temperature when B is higher than BCL and BCI. The effect of temperature becomes striking while B is close to BCL or BCI. The results also show that the farther from the interface the electron, the more markedly the electronLO phonon interction changes with the variation of temperature. On the other hand, the nearer from the interface the electron, the more distinctly the electronIO phonon interaction changes with varying temperature.

Cyclotron Resonance of Free Magnetopolaron in Quantum Well Wires

The cyclotron resonance of magnetopolaron in quantum well wires (QWWs) have been studied with the use of variational solutions to the effective mass equation. The results show that both the abso- lute value of the electron-phonon interaction energy and the cyclotron resonance frequency de- crease with the increase of the sizes of QWWs, and also that the cyclotron resonance frequency in- creases with the external magnetic field.

The optical phonon drag effect on strong-coupling decay magnetopolaron in Gaussian alkali halogen ionic quantum wells

The polaron phenomenon is commonly observed in low-dimensional semiconductor materials and is known to have unique effects on conductive material properties.Furthermore,the phonon dragging effect,which leads to the polaron energy level,is less than the electron energy level.A decay magnetic field also affects the polaron effect,which causes polaron energy level changes.We demonstrate the unique electron-phonon coupling properties of this polaron using numerical calculations.Our findings have strong implications for theories of polaron properties and provide compelling evidence for a semiconductor device that industrial manufacturers use for new lowdimensional materials.

Magnetic field and temperature dependence of the properties of the ground state of the strong-coupling bound magnetopolaron in quantum rods with hydrogenic impurity

Magnetic field and temperature dependence of the properties of the ground state of the strong-coupling bound magnetopolaron in quantum rods （QRs） with hydrogenic impurity is studied by means of the Huybrechts- Lee-Low-Pines transformation method and the quantum statistical theory. The expressions for the ground-state energy and the mean number ofphonons of the magnetopolaron are derived. Results of the numerical calculations show that the bound state of the magnetopolaron cannot be formed when the value of the aspect ratio of the QR, the dielectric constant ratio, the electron-phonon coupling strength or the temperature parameter is small. The larger the deviation of the value of aspect ratio e′ from 1 is, the more it is unfavorable to the stability of the ground state of the magnetopolaron. When the magnetopolaron is in the bound state, the absolute value of its ground-state energy and its mean number ofphonons increase with an increase of the dielectric constant ratio and confinement strength of QRs, but decrease with an increase in the cyclotron frequency of the external magnetic field and the temperature. The absolute value of the ground-state energy and the mean number of phonons of the magnetopolaron decrease with decreasing e′ when e′ 〈 1, but decrease with increasing e′ when e′ 〉 1. They get the maximum value at e′=1.

Properties of the magnetopolaron in a triangular quantum well

We study the properties of the magnetopolaron in a triangular quantum well within LLP variational method. At different electron-phonon coupling strength, we derive the relations between the ground state energy, the ground state binding energy with the electron areal density and the cyclotron frequency of magnetic field, respectively. Our numerical results show that the ground state energy is an increasing function of the electron areal density and the cyclotron frequency of the magnetic field. However, the ground state binding energy is a decreasing function of those.

Magnetopolaron effects on the optical absorptions in a parabolic quantum dot

We investigate the influence of magnetic field on the linear and nonlinear optical absorptions in a parabolic quantum dot（QD） through electron-LO-phonon interaction by using the Lee-Low-Pines-Huybrecht variational calculation for all coupling strengths.We apply our calculations to GaAs which is a good candidate in Ⅲ-Ⅴgroup semiconductors.We find that all the absorption spectra are strongly affected by the electron-LO-phonon interaction,the applied magnetic field,and the Coulomb binding potential.Furthermore,due to the Zeeman splitting,the response of all the absorption values in transition（＋1→0） and（-1→0） closely depends on the magnetic field increasing.