Dear All,

This is a question about the CASTEP module.

The structure I want to calculate is the insulator.
spin is 1 system.

So I tried to calculate by checking the fix occupancy, but you have to use smearing to use the spin optimization option in CASTEP Occupancy Options (CASTEP Electronic Options > SCF > More..).

Can't I use the spin optimization option while using the Fix occupancy option?

*This is to use b3lpy or pbe0 functional in the Band Structure Options calculation. (use separate XC functional for band structure calculation)

Can someone explain this to me?