| name | band-advanced |
| description | Advanced Band Structure Methods (3 sub-skills: 3d-band-structure, band-unfolding, hybrid-dft-bands) |
Advanced Band Structure Methods
Overview
This skill group covers advanced electronic band structure techniques beyond the standard k-path band calculation. These methods address specific challenges in electronic structure theory: visualizing the full Brillouin zone dispersion for 2D materials, obtaining accurate band gaps with hybrid functionals, and recovering effective primitive-cell band structures from supercell calculations.
Sub-Skills
| Sub-Skill | Directory | Description |
|---|
| 3D Band Structure | 3d-band-structure/ | Full E(kx,ky) surface over the 2D BZ for layered/2D materials (VASPKIT 231-233) |
| Hybrid-DFT Bands | hybrid-dft-bands/ | HSE06/PBE0 band structures with accurate band gaps (VASPKIT 250-257) |
| Band Unfolding | band-unfolding/ | Unfold supercell bands back to primitive BZ to reveal effective band structure (VASPKIT 281-285) |
Method Decision Guide
Need advanced band structure analysis?
|
+--> Full BZ dispersion for 2D material?
| YES --> 3d-band-structure/
|
+--> Accurate band gap (hybrid functional)?
| YES --> hybrid-dft-bands/
|
+--> Supercell with defect/alloy/interface, want primitive-cell-like bands?
YES --> band-unfolding/
Common Prerequisites
- Converged structure: Always start from a well-relaxed structure (use
scf-relax skill).
- Pseudopotentials: QE calculations require pseudopotential files. Use SSSP or PseudoDojo libraries.
- Python environment:
pymatgen, ase, numpy, scipy, matplotlib are pre-installed. Install extras with pip install seekpath as needed.
- QE executables:
pw.x, bands.x, pp.x, projwfc.x (Quantum ESPRESSO 7.5).
- MACE limitation: MACE is a machine-learning force field and cannot compute electronic band structures. Use it only for structure pre-relaxation before DFT.
Important Notes
- Standard PBE band gaps are underestimated by 30--50%. Use hybrid-DFT bands for quantitative gap values.
- 3D band structure calculations require dense k-meshes and are significantly more expensive than standard k-path calculations.
- Band unfolding is essential when studying defects, alloys, or interfaces in supercells -- without it, the zone-folded bands are uninterpretable.
- All three sub-skills share the same SCF foundation. A well-converged SCF charge density is the starting point for each method.
