  GdN is a ferromagnetic semiconductor which has seen increasing interest in
the preceding decades particularly in the areas of spin- and superconducting-
based electronics. Here we report a detailed computational study and optical
spectroscopy study of the electronic structure of stoichiometric and nitrogen
vacancy doped GdN. Based on our calculations we provide the effective mass
tensor for undoped GdN, and some indicative values for electron doped GdN. Such
a property is valuable as it can directly affect device design, and be directly
measured experimentally to validate the existing computation results.
