I would like to ask a question about the plot of density of state. Taking the attached figure as an example, What does the energy (X axis) and the DOS (Y axis) mean, respectively?
In my understanding, DOS means the number of orbitals which are hybrid to each other at the same energy level. is it right to understand it like so?
Besides, could you explain the meaning of "energy" in the X-axis? what is the difference between negative and positive energy? Thank you very much.