A Study Of The Properties Of Bound Polaron Low-energy States In Pseudo-quantum Dots

When the quantum pseudodot material has structure inversion asymmetry,the interaction between the spin and orbital motion of the electron will lead to the Rashba effect,which makes the degenerate elimination of the bound polaron energy level of the quantum pseudodot partially eliminated.At the same time,the polaron properties of quantum pseudodot are also easily affected by factors such as temperature and pressure.Therefore,it is necessary to study the low-energy state properties of the bound polaron under the influence of the Rashba effect in the quantum pseudodot system and the influence of temperature on its properties.In this paper,we mainly study the low-energy state properties of bound polaron of the quantum pseudodot under the Rashba effect.At the same time,we also study the influence of the temperature on the oscillation period properties of the low-energy state of the quantum pseudodot in the presence of the Rashba effect.Theresearching process and main conclusions are as follows:(1)In the case of effective mass approximation,the Hamiltonian of the quantum pseudodot system is obtained when the Rashba effect is considered.By using the Lee-Low-Pines(LLP)type unitary transformation and the Pekar variational idea,the energy of the low-energy state of the system and the corresponding trial wave function are obtained;the probability density and excitation energy of the bound polaron of quantum pseudodot under the influence of Rashba effect are studied.Numerical calculation results show that:(i)when the bound polaron is in the superposition state of the ground state and the first excited state,the probability density changes periodically in time and space,and its amplitude oscillates periodically.This characteristic does not change with the electron-LO phononcoupling strength;(ii)the excitation energy is split into three different branches by the Rashba spin-orbit interaction,and the splitting phenomenon does not vary with the phonon wave vector,two-dimensional electron gaschemical potential,Coulomb binding potential,electron-LO phonon coupling constant and Rashba coupling strength;(iii)different branches of the excitation energy have different increasing or decreasing trends with the change of acoustic wave vector;(iv)the excitation energy is an increasing function of the two-dimensional electron gas chemical potential,Coulomb binding potential,electron-LO phonon coupling constant and Rashba coupling strength;(v)the two-dimensional electron gas chemical potential,electron-LO phonon coupling constant,Coulomb binding potentialand Rashba coupling strength do not make the changing trend of excitation energy and phonon wave vector change.(2)By applying LLP type unitary transformation,Pekar variational idea and Quantum statistical theory,the oscillation period of the bound polaron in superposition state is derived in detail.The influence of temperature on the oscillation period of the bound polaron in the quantum pseudodot under the effect of Rashba spin-orbit interaction is also investigated.Numerical calculation results show that:(i)the oscillation period is split under the influence of the Rashba spin-orbit interaction,and does not change with the changes of the phonon wave vector,electron-LO phonon coupling constant,Coulomb binding potential,two-dimensional electron gas chemical potential and Rashba coupling strength;(ii)when the values of the phonon wave vector,electron-LOphonon coupling constant,Coulomb binding potential,two-dimensional electron gas chemical potential and Rashba coupling strength are different,the oscillation period rises with increasing temperature;(iii)the amplitude of the oscillation period is affected by the phonon wave vector,electron-LO phonon coupling constant,Coulomb binding potential,two-dimensional electron gaschemical potential and Rashba coupling strength,but the influence degree and the increasing and decreasing trend are different.Our theoretical results show that many factors can affect the properties of low energy states of electrons and polarons in quantum pseudodot,and different methods can be selected to control the properties of electrons and polarons in quantum pseudodot according to the needs of designing and manufacturing quantum pseudodot.