3 Gap States

From here you may load this preset , see the text of the next , or return to the preset list.

This is the same band structure as preset 1, but let's focus on the energy gaps. Clicking on band list gives a text window with the energies of the edges of the bands listed (probably to higher precision than that of the calculation).

In the left display is the electron density for a state of energy, 0.65 eV, near the bottom of the second energy gap. If the increasing amplitude moving to the right continues (as it does) you see why this is a physically inadmissible solution for an infinite crystal. (It may be of interest, however, if there is a surface not far to the right.)

Using the double click scheme, explore the psi-squared plots for energies throughout the 2nd gap. (If you zoom the energy axis to include only this gap and little of the neighboring bands, it is easier to explore what happens close to the band edge.) How does the strength of the exponential decay depend upon whether the energy is deep within the gap or near the band edge, but still in the gap?