| Summary: | The 1/N expansion method has been used to investigate the problem of an electron moving in a two-dimensional semiconductor quantum ring with an off-center impurity. The energy spectra, magnetization, and magnetic susceptibility have been calculated as a function of the magnetic field, impurity position, temperature, and quantum ring parameters. Interesting energy-level crossings attributed to QR confinement manifest themselves as low-temperature oscillations in the magnetization and magnetic susceptibility curves. On the contrary, the presence of impurity at the QR center eliminates these level crossings. This work shows that changing the impurity position can manipulate the magnetic field value correspondence to these diamagnetic-paramagnetic phase transitions.
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