Donor binding energy under magnetic field in cylindrical nanotube with two GaAs/GaAlAs quantum wells

A systematic study of the binding energy of the ground state of a hydrogenic off-axis donor in a cylindrical quantum wire containing two quantum wells in a section of the tube layer is calculated in the presence of a uniform magnetic field applied parallel to the wire axis with different potential shape. We express the wave function as a product of combinations of s and p subband wave functions and an envelope function that depends only on the electron-ion separation. By using the variational principle we derive a differential equation for the envelope function, which we solve numerically. Two peaks in the curves for the dependence of the ground-state binding energies on the donor distance from the axis are presented and it is shown that the increasing the magnetic field increasing the binding energy while the impurity is located in the QW1, whereas the opposite occurs when the impurity is located in the QW2.