A crystal has two bands of interest

PHYSICS · Subjective · Fermi University Physics · Condensed Matter, Materials & Soft Matter · Free electrons, energy bands and electronic structure · Free electrons, energy bands and electronic structure

Condensed Matter Physics, Ch Tight binding, band filling and the three kinds of solid

Problem

A crystal has two bands of interest. Band A is

8.0\ \mathrm{eV}

wide, built from a conduction electron perturbed by a periodic potential of amplitude

|U_G| = 0.40\ \mathrm{eV}

. Band B is

1.2\ \mathrm{eV}

wide, built from an atomic level whose neighbouring levels sit about

6.0\ \mathrm{eV}

away. Using the chapter's criterion, say which picture, nearly-free-electron or tight-binding, better describes each band, and justify each choice with a ratio.

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