Prepare VASP band-structure workflow inputs from existing SCF context and user-specified band-path settings. Use when the user requests electronic band-structure calculations and needs explicit prerequisite checks, line-mode KPOINTS path setup, and stage-specific INCAR preparation.
This skill prepares band-structure-stage input tasks only. It verifies
prerequisite SCF context, generates line-mode KPOINTS, and prepares a
stage-appropriate INCAR. It does not submit or execute jobs.
Per VASP wiki Fcc_Si_bandstructure:
LCHARG = .TRUE. on a regular Monkhorst–Pack
/ Γ-centered mesh (done by dft-vasp/static).ICHARG = 11),
sample along a high-symmetry path using line-mode KPOINTS, and use
Gaussian smearing (ISMEAR = 0) — not tetrahedron, because line-mode
meshes are not suitable for tetrahedron integration.VASP wiki: "This calculation needs a converged charge density as input (ICHARG=11)."
CHGCAR (non-empty) from a prior SCF/DOS runPOSCAR, POTCAR, ENCUT, PREC, GGA as the prerequisite SCFLCHARG = .TRUE.If any of these is missing, stop and ask.
| Tag | Role | Recommended |
|---|---|---|
ICHARG | charge handling | 11 |
ISMEAR | k-sampling method | 0 (Gaussian, SIGMA = 0.05) |
LORBIT | projection mode | 11 for fat/projected bands, omit for plain |
NBANDS | extra bands | ≥ 1.3 × occupied to resolve conduction manifold |
LWAVE, LCHARG | do not overwrite | .FALSE., .FALSE. |
L – Γ – X – U | K – Γ.Γ – H – N – Γ – P.Γ – M – K – Γ.sumo-kgen or seekpath (or pymatgen-structure's
high-symmetry helper) — never guess coordinates.Line-mode KPOINTS exactly as in VASP wiki Fcc_Si_bandstructure
(L – Γ – X – U, then K – Γ, 20 points per segment):
k-points for bandstructure L-G-X-U K-G
20
line
reciprocal
0.50000 0.50000 0.50000 1 ! L
0.00000 0.00000 0.00000 1 ! Gamma
0.00000 0.00000 0.00000 1 ! Gamma
0.00000 0.50000 0.50000 1 ! X
0.00000 0.50000 0.50000 1 ! X
0.25000 0.62500 0.62500 1 ! U
0.37500 0.75000 0.37500 1 ! K
0.00000 0.00000 0.00000 1 ! Gamma
INCAR:
SYSTEM = fcc Si band
ISTART = 1
ICHARG = 11
ENCUT = 320
PREC = Accurate
LREAL = .FALSE.
EDIFF = 1E-6
NELM = 60
ISMEAR = 0
SIGMA = 0.05
LORBIT = 11
LWAVE = .FALSE.
LCHARG = .FALSE.
grep -c 'BZINTS' OUTCAR — should be 0 (line-mode k-points must not
trigger Brillouin-zone integration warnings).ls EIGENVAL — file must exist and be larger than POSCAR.head -6 EIGENVAL — line 6 reports NELECT NKPTS NBANDS (for the
fcc Si 4-segment × 20-point example: 4 80 8, i.e. 4 valence
electrons, 80 k-points along the path, 8 bands auto-picked by VASP).EIGENVAL (or vaspkit 211, sumo-bandplot): verify connectivity
— the bands must follow the path without gaps in the k-axis.ICHARG = 11 with ISYM ≠ 0 on a low-symmetry path sometimes
symmetry-reduces k-points you wanted to sample. Set ISYM = 0 if the
resulting NKPTS is smaller than the number of requested line points.LHFCALC = .TRUE.) cannot use
ICHARG = 11 line-mode directly — use the zero-weight-KPOINTS trick
or LOPTICS/wannier90 path.INCAR, line-mode KPOINTS,
staged CHGCAR from the prerequisite SCFdpdisp-submit