I'm trying to converge a dilute fcc alloy consisting of Cu and U, with the Uranium concentration at 0.01% and the lattice parameter of Cu, using Hubert Ebert's Spin Polarized Relativistic Korringa-Kohn-Rostoker (SPR-KKR) program.

However it seems that after one iteration the energy of the lower limit of the semi-core states shoots above the upper energy limit of the core states. This problem only started to arise when I introduced the valence of the Cu and U atoms as parameters. I set the valence of U as 12 and the valence of Cu as 10, but have also tried 1 for the Cu valence. I have tried lowering the energy range of my calculation but that also doesn't seem to work, now I'm stuck and I'm not sure what other troubleshooting options to do.

  • $\begingroup$ Maybe I can write to Hubert Ebert and see if we can get an answer that way. $\endgroup$ Sep 10 '20 at 3:16
  • $\begingroup$ I've sent the email now to Prof. Dr. Ebert. Let's see if he answers it here now. $\endgroup$ Oct 6 '20 at 23:01
  • $\begingroup$ Hi Nike, I think the issue I had was actually with my starting potential, I find that starting with a pure U structure in a Cu lattice and then converging the potentials from previous whilst increasing the Cu concentration until eventually I'm at 99% Cu conc. solves the issue. $\endgroup$
    – LUPHYS
    Oct 8 '20 at 14:00
  • $\begingroup$ please write an answer then. Unamswered questions can be harmful to our site and community. $\endgroup$ Oct 8 '20 at 14:04

I managed to get the converged U$_{0.01}$Cu$_{0.99}$ potential by converging a pure Uranium potential in a Cu lattice. Then by increasing the concentration of Cu and using the old converged potential as a starting potential you can increase the concentration of Cu in steps until finally reaching a converged U$_{0.01}$Cu$_{0.99}$ potential. This is a good method to try in any binary alloy system if you have a point that doesn't seem to converge.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.