Investigation of electronic bound states of a radially modulated nanowire: Level anti-crossing and bound states in continuum.

In this paper the electronic confinement energy states of a radially modulated cylindrical nanowire are numerically calculated, assuming that the modulated section has finite length and its radius is greater than the remaining section of the nanowire. The Schrodinger equation is solved within the effective mass approximation using the finite element method to specify the necessary conditions for emersion of 3-dimensionally confined states and to investigate size and magnetic field dependence of the confinement energies. Our results show that for any local increment of nanowire radius, there is at least one bound state for each channel of angular momentum. The energies of bound states of higher angular momentum are shown to lie in the energy continuum of lower angular momentums. In addition, there is some level crossing and anti-crossing in the size dependence of confinement energies which can be explained on the basis of symmetry. It is observed that in the vicinity of the level anti-crossing, the oscillator strengths associated to intersubband transitions from ground state change dramatically and vanish for some specific width of modulation. [ABSTRACT FROM AUTHOR]