Hello all, I'm getting confusing about what to consider as a barrier for electron tunneling in DFT. What I'm doing is looking at the xy plane averaged effective potential, i.e. the potential that electrons feel. This potential in PAW formalism is composed of three terms: VHartree+Vxc+Vbar, where VHartree is the electrostatic potential, Vxc-exchange correlation, Vbar - unphysical correction. My system is periodic in xy and non-periodic in z. As I understand, if there is a barrier, effective potential should go a bit over the Fermi level. I don't see this in my case. What I encounter in some papers is that they look at only electrostatic(Hartree) contribution. If I plot only electrostatic potential + Vbar correction then there is some portion of plot above Fermi level. So, which one can be considered as a tunneling barrier, total effective potential or only electrostatic? Thank you for any help.