Influences Of Rashba Efeect And Temperature On The Properties Of Polaron In Quantum Wires

In this paper, by using improved linear combination operator and unitary transformation methods, the properties of strong coupling bound magnetopolaron in semiconductor quantum wire with influence of Rashba spin-orbit interaction are studied. Thus its effective mass, ground state energy and interaction energy are derived. Numerical calculations performed on RbCl crystal show that its effctive mass relates to not only the polaron’s velocity, virbration frequency, confinement strengh, cycltron frequency but also electron areal density. And the relation curves of it versus the above quantities are all split into two branches, which is caused by the Rashba effect. Its interaction energy relates to not only spin-orbit coupling constant but also vibration frequency, and it will increase sharply until a certain value then sharply decrease with increasing the vibration frequency.Secondly, we use the same methods to study the properties of the weak coupling bound polaron considering the influence of Rashba effect, in the semiconductor parabolic quantum wire. Then its vibration frequency, effective mass, ground state energy, ground state splitting energy and interaction energy are derived. Numerical results performed on GaAs crystal show that its ground state energy and effective mass split into two branches, the effective mass ratio will increase with increasing the electron phonon coupling strength. The effective mass ratio will linearly increase with increasing the electron areal density when the spin is up, the reverse conclusion will obtain when the spin is down. The effective mass ratio will decrease with increasing the polaron’s speed. As the vibration frequency increases, ground state energy and its splitting energy increase, whereas the interaction energy will increase sharply until a certain value then decrease. Consequently, the Rashba effect should not be ignored when considering the polaron’s problems.Finally, the temperature effect of polaron in the cylindrical quantum wires is studied by using a combinative approach of precisely solving the schrodinger equation, the LLP unitary transformations and variational methods. The numerical results show that, when γ>1or kBT<hωLO, the ground and excited state energy will not change with temperature, which is because the phonon will not be excited under low temperature; when0<γ<1or kBT>hωLO, they will increase with increasing the temperature, which is because under high temperature the electron’s energy of heat sport will increase and more phonons will be excited. When the temperature is fixed, they will decrease with increasing the semidiameter of the cylindrical quantum wires, which indicates that quantum wires have apparent quantum size effect. Moreover, they will decrease with increasing the electron phonon coupling strength, which is because the absolute value of electron phonon interaction energy is bigger when the electron phonon interaction is stronger.