# berry keywords

Berry phase calculator

## berry.bandIndex

Band index for which the Berry curvature is calculated.

**type**: `scalar`

**example**: `berry.bandIndex = 17`

## berry.includeVnl

If true, the Berry calculation takes the non-local pseudopotential
commutator into account (\[r,vnl\]). This term is often negligible but
it is included by default nevertheless.

**type**: `scalar`

**default**: `true`

**allowed**: `true,false`

**example**: `berry.includeVnl = 0`

## berry.bandRange

Band indices of the bands entering the Berry curvature definition, i.e.
those included in the velocity matrix definition. The default value is
all the bands given by eigensolver.bandi; often, a few bands around the
band given by berry.bandIndex is sufficient.

**type**: `array`

**example**: `berry.bandRange = [1,17]`
