Sorry for English typing. I don't know what happened between professors. Maybe you are right. If the student told the truth, Dr. Nam could be still the 1st author. He had a primitive idea, and organized the experiment. Usually, professor wouldn't do an experiment directly. I am not sure since I am a theorist, but in this area, usually students still calculate almost everything as possible. Professor just guesses what would happen. However, I don't wanna underestimate the contribution by professor. Making an idea is not easy. However, I also think the student deserves to be a secondary author. I don't know why the professor didn't include the name of the student.