Aharonov-Bohm Oscillations And Magnetization Of Biexcitons In A Quantum Ring Under Magnetic Fields

In this paper,the properties of Aharonov-Bohm(AB) oscillations and magnetization of biexcitons in a quantum ring under magnetic fields are studied theoretically in the framework of effective-mass envelope function.Within one-dimensional quantum ring model,the Hamiltonian of the biexcitons complex are simplified to reducing the variable in order to easily calculate,then the energies and the magnetization of the systems can be achieved by using exact diagonalization techniques.The results are discussed in detail,the results indicate:(1) The coulomb interactions of the charged particles have effect on AB oscillation of the systems in the biexcitons systems.The oscillations are generated by transitions of the energies of different angular momentums.As we increase the radius,the coulomb interactions are weak and the configurations with more different angular momenta are mixed.Because of the transitions are more frequently,so the ground-state energy depends smoothly on the number of magnetic flux.In the same way,when the increasing radius bring the decrease of the total coulomb interactions and the magnetic field,because of the influence of the magnetic field is small compared to the coulomb interactions on energies,the AB oscillation becomes more and more gentle.Once again to strengthen the total coulomb interaction,AB oscillations of the ground-state and the low excited-state energies are not obvious.(2) When the radius of the quantum ring is fixed,the ground-state energy is raise or drop changing with magnetic flux,but the total tend is raise.The amplitude of energy is decrease with the increasing radius.The configuration of ring effects the coulomb interactions of the charged particles and the oscillation of energy.When the radius of quantum ring is gradually increasing,the curvature of ring is more and more small.The movement of every particles in the ring is more and more tend to the movement in the one-dimensional infinitely deep potential well.At this time,the periodic variation of the ground-state energy is weak by degrees,until become monotonous increase with the magnetic flux.(3) With the increasing radius,the contribution of the coulomb interaction is even greater compared to the contribution of the magnetic field to the system.The magnetization oscillations with increasing magnetic field are less unclear.The general trend of the magnetization oscillations with the magnetic field is low. (4) When the absence of the interactions,the magnetization oscillations are stronger. When the N_φare 0.5 and 1.5,the magnetization is from the negative number to the positive number.When the presence of the interactions,the magnetization oscillations are gently,and the total tend of oscillations is low.