Energy alignment
| Mode | Meaning | Appropriate interpretation |
|---|---|---|
| Source energy | Keep the numerical reference as imported. | Use only when source conventions are understood. |
| Each Fermi = 0 | Shift every dataset by its own recorded Fermi level. | Compare dispersion shapes relative to each electronic chemical potential; not absolute band offsets. |
| Each VBM = 0 | Shift by a recorded valence-band maximum. | Compare band-edge-relative features when the VBM is meaningful. |
| Vacuum alignment | Use a recorded vacuum reference. | A common-reference comparison when vacuum levels are physically justified. |
| Manual shift | Apply a stated explicit energy offset. | Use a documented alignment procedure and retain the chosen offset. |
Band + DOS
A verified pair requires matching recorded geometry and electronic source identity, along with compatible Fermi-relative data. A matching filename or material formula alone is insufficient.
The paired layout gives band and DOS panels a shared physical vertical energy axis, typically in a 2:1 width ratio. Adjusting a linked energy bound updates both panels.
Replacing one source with an unrelated calculation invalidates the verified-pair claim. Use ordinary comparison panels when sources are intentionally different.
K-path compatibility
The labels Γ, X, or K are not enough to establish the same reciprocal coordinate. Cell basis, path endpoints, and segment coordinates matter.
Physical path comparisons require compatible source geometry and coordinates. Segment normalization can align corresponding endpoints when the required metadata exists, but changes the displayed horizontal scale.
Disconnected branches must remain separated by gaps. Do not connect their endpoints into a fictitious continuous band.
DOS normalization and spin
- Per-cell DOS is the default meaning of many QE outputs. Do not silently label it per atom.
- Per-atom normalization needs a verified atom count; per-formula-unit normalization needs the formula-unit count; per-volume normalization needs a valid cell volume.
- Spin-down mirroring reflects a channel visually to distinguish it. It does not make physical DOS negative.
- Inspect whether a channel is total DOS, an orbital/atom projection, or an arbitrary imported column. Channel names should state the actual meaning.