Where does band collide?

In a crystalline solid, a band is a continuous range of energies that an electron is allowed to occupy, formed when the discrete levels of many atoms broaden and merge together. Wilson's 1931 band theory explained conduction this way: allowed bands are separated by forbidden gaps, and whether a material conducts, insulates, or semiconducts depends on how the highest occupied band sits relative to the gap above it. The referent is a set of quantum states inside a material, and the unit is energy, given in electronvolts. Nothing here is a group of people or a region on a graph; the word names the permitted energies themselves and the band gap that divides them.[1]

Unit

A range of allowed electron energies (eV)

Recovery means

Not applicable

Measured by

Band structure computed from theory or read off by spectroscopy; the band gap in electronvolts

A confidence band, or prediction band, is the region drawn around a fitted curve that is expected, at a stated level, to contain the true curve or a future observation. Working and Hotelling introduced the idea in 1929 for a fitted trend line, giving simultaneous limits that hold across the whole range of the predictor rather than at a single point. The referent is a zone on a graph, and its unit is that of the response variable, its half-width narrowing where data are dense and widening at the extremes. It is a statement about uncertainty, not a group of players and not a set of electron states.[2]

Unit

A region around a fitted curve

Recovery means

Not applicable

Measured by

The half-width of the band at a chosen confidence level, from the fitted model and its error