I want to do a GGA+U calculation on the LaAlO3/SrTiO3 heterostructure to study the 2DEG formed at the interface. In all the references I came across they used U around 4eV-6eV on Ti 3d orbitals, I'm okay with this. However, they also use a high U value of 9eV-11eV on La 4f orbitals, "to avoid spurious mixing with Ti d bands". I don't understand why is this important and why add U on f electrons which are not even valence electrons for La.

  • $\begingroup$ Please attache the refrence of the paper. $\endgroup$ Mar 2 at 17:59