I’m trying to do some very basic defect calculations in a class of complex oxides with the stoichiometry AB6O12, where A=U,W,Re and B=Y,Yb,Lu. In most cases, especially when A=W, I haven’t had any problems. But, I have had problems with convergence in two cases that I haven’t been able to make any progress on. When A=U and B=Y, I can converge the perfect structure very nicely. But, when I look at an antisite defect, by replacing one Y with U, the calculation doesn’t converge. The electronic iterations get stuck, changing by +/- the same amount. A number of colleagues have suggested I change the smearing, set ISPIN=2, set LMIXMAX=6, etc. Everything I’ve tried, either doesn’t change the behavior or does fix the electronic iterations, but after 3 or 4 ionic iterations, the forces on the ions blow up (become unphyiscally large, like 100 eV/angstrom). The second problem, when A=Re and B=Lu, is that I don’t get any kind of convergence, even in the perfect case. I get a warning at the top VERY BAD NEWS! internal error in subroutine IBZKPT:
Reciprocal lattice and k-lattice belong to different class of lattices. 168 But all I’ve done compared to the A=U, B=Y case is change the POTCAR file. If I let it go, I get similar convergence problems as before.
Any help will be apprecited.
I didn’t find the right solution from the Internet.
Construction solution Video