Hi, I use Material Studio 2018. I want to generate CeO2(111) surface with geometry optimization in CASTEP. I  selected GGA-PBE and LDA+U (U=6 eV for Ce f orbital). Also, I must select 'spin-polarized' for Hubbard parameter. After SCF cycles (9999 cycles), electronic minimisation did not converge.  How can I solve this problem? Does anyone have any idea? Thanks

Sincerely