Unusual Diamagnetism in Semiconductor Nano-Objects

We theoretically consider the diamagnetic response of an InAs/GaAs asymmetrical nano-ring and asymmetrical quantum dot molecule when external magnetic field is applied in the system’s growth directions. We use the effective one-electronic-band Hamiltonian (energy-position-dependent electron effective mass and g-factor approximation) with smooth full three-dimensional confinement potentials mapping actual strain and material content in those nano-objects. This approach allows us to simulate and study physical properties of semiconductor nano-objects within a wide range of change in geometry and parameters. Although the geometries of the systems investigated are very different, we found for both systems a similar magnetic response. At low temperature the single electron differential magnetic susceptibility has a positive peak and with temperature increasing the peak remain Lorenzt-like shaped and gradually disappear.