VASP should be compiled with CP-VASP module (https://github.com/yuanyue-liu-group/CP-VASP/)

Example cluster settings for SIMAN:

CLUSTERS['raz128_cp'] = {
# 'address':'a.boev@10.30.98.103',
'address':'raz128',
'vasp_com':'srun vasp_std',
'homepath':'/home/a.boev/',
'schedule':'SLURM',
'corenum':16,
'modules': 'source /etc/profile.d/modules.sh; \
module load devtools/mpi/mpich/4.2.1/gcc/11.2; \
module load q-ch/qe/7.3.1/gcc/11.2/mpich/mkl; \
module load q-ch/cp-vasp/6.3.2_mpich_mkl; \
\nulimit -s unlimited\n\
'
}

1. Construct a slab model with:

• sufficiently large vacuum region (recommended: ≥ 20 Å)
• symmetric slab if possible

2. Obtain migration pathway. Generate NEB images for the Li migration process using standard vacuum calculations. At this stage CP-VASP is not yet required. These NEB images will later be reused for constant-charge (CC) and constant-potential (CP) single-point calculations.

3. Constant-charge (CC) calculations. Perform single-point calculations for all NEB images using implicit solvent conditions. Recommended INCAR additions:

'LDIPOL':None, 
'IDIPOL':None,
'LSOL':True,
'ISOL':2, 
'EB_K':89.78,

This step provides migration profile under fixed electron number. The obtained Fermi level can be used as an initial estimate for TARGETMU in CP calculations.

4. Constant-potential (CP) calculations Use the same NEB image geometries from step 2 and perform CP-VASP calculations with:

'LDIPOL':None, 
'IDIPOL':None,
'LSOL':True,
'ISOL':2, 
'EB_K':89.78,
'LCEP':'.TRUE.', 
'NESCHEME': 1, 
'TARGETMU' : XXX, 
'CAP_MAX':2, 
'FERMICONVERGENCE':0.01,

where TARGETMU is the target electronic chemical potential (in eV). Values around the slab Fermi level are typically tested:

TARGETMU = Efermi ± Δμ
Δμ = 0.5 or 1 eV

A practical starting point is the Fermi level of the slab calculated under implicit solvent conditions.

For electrochemical systems different TARGETMU values correspond to different electrode potentials, CP calculations allow electron exchange with the external reservoir.

For transition-metal oxides (LCO, NMC, etc.) DFT+U may lead to charge localization, polaron formation, metastable electronic states. Therefore it is strongly recommended to use continuation calculations, reuse WAVECAR and CHGCAR between neighboring images, avoid restarting every image from scratch.

Test of magnetism and Hubbard