I am trying to use the natural band offset method to calculate band offsets of junctions. In order to do so, I need to find the core electron eigenstates. I tried using FP-LAPW software Elk. But in the output of the core electron eigenstates there is a "k" value.
The value is listed among "n" and "l", so my thought is that it may a quantum number. But I am not sure. I was able to find that it may be the "projection of the total spin I on the nuclear symmetry axis". Could someone help me identify what k means?