Schematic band structure of a semiconductor (the allowed energy bands versus
Electrons which are excited (e.g. by a laser pulse) from the valence band to the conduction band, leave a hole in the valence band.
If many electrons are excited at the same time the remaining holes can show gas-like, liquid-like or crystal behavior. Which of these behaviors appears, depends on the hole (valence) band curvature.
|Hole crystal (A)||Hole liquid (B)||Hole gas (C)|
See Animations of the computer simulations results corresponding to three of the snapshots above.
Here we also resolve the electron and hole spins (electrons: yellow and blue dots, holes: red and
pink dots correspond to different spin orientations). Beware: large files!
hole crystal (M=100, 5 MB)
hole fluid (M=25, 5 MB)
hole gas (M=5, 5 MB)
Right animation shows a combination of the electron-hole state in momentum and real space shown in the figures above. The valence band curvature (mass ratio M) cycles through the values 5-12-25-50-100
Animation due to Gerald Schubert, Univ Greifswald