Global Parameters
ISTART =  1            (Read existing wavefunction, if there)
ISPIN  =  1            (Non-Spin polarised DFT)
# ICHARG =  11         (Non-self-consistent: GGA/LDA band structures)
LREAL  = .FALSE.       (Projection operators: automatic)
# ENCUT  =  400        (Cut-off energy for plane wave basis set, in eV)
# PREC   =  Accurate   (Precision level: Normal or Accurate, set Accurate when perform structure lattice relaxation calculation)
LWAVE  = .TRUE.        (Write WAVECAR or not)
LCHARG = .TRUE.        (Write CHGCAR or not)
ADDGRID= .TRUE.        (Increase grid, helps GGA convergence)
LASPH  = .TRUE.        (Give more accurate total energies and band structure calculations)
PREC   = Accurate      (Accurate strictly avoids any aliasing or wrap around errors)
# LVTOT  = .TRUE.      (Write total electrostatic potential into LOCPOT or not)
# LVHAR  = .TRUE.      (Write ionic + Hartree electrostatic potential into LOCPOT or not)
# NELECT =             (No. of electrons: charged cells, be careful)
# LPLANE = .TRUE.      (Real space distribution, supercells)
# NWRITE = 2           (Medium-level output)
# KPAR   = 2           (Divides k-grid into separate groups)
# NGXF    = 300        (FFT grid mesh density for nice charge/potential plots)
# NGYF    = 300        (FFT grid mesh density for nice charge/potential plots)
# NGZF    = 300        (FFT grid mesh density for nice charge/potential plots)
 
Electronic Relaxation
ISMEAR =  0            (Gaussian smearing, metals:1)
SIGMA  =  0.05         (Smearing value in eV, metals:0.2)
NELM   =  90           (Max electronic SCF steps)
NELMIN =  6            (Min electronic SCF steps)
EDIFF  =  1E-08        (SCF energy convergence, in eV)
# GGA  =  PS           (PBEsol exchange-correlation)
 
Ionic Relaxation
NSW    =  100          (Max ionic steps)
IBRION =  2            (Algorithm: 0-MD, 1-Quasi-New, 2-CG)
ISIF   =  2            (Stress/relaxation: 2-Ions, 3-Shape/Ions/V, 4-Shape/Ions)
EDIFFG = -2E-02        (Ionic convergence, eV/AA)
# ISYM =  2            (Symmetry: 0=none, 2=GGA, 3=hybrids)
 
