We present a theoretical platform for modeling the electronic and magneto-optic properties of magnetically doped core-shell nanoparticles that has, as a central prediction, a mechanism by which the $g$ factors in these nanoparticles can be tuned over a wide range by controlled positioning of magnetic impurities. We illustrate this effect for wide-gap Mn-doped CdS-ZnS core-shell particles and point out several unexpected trends that merit extended experimental investigation. The ability to tune $g$ factors will make core-shell nanostructures viable candidates for spintronic applications, and the comprehensive modeling approach outlined here will be a powerful tool for predicting their properties as well as for optimizing the design of novel spintronic devices.

• Received 20 October 2015
• Revised 3 February 2016

DOI:https://doi.org/10.1103/PhysRevB.93.075431