POPULATION-INVERSION OF LANDAU-LEVELS IN THE VALENCE-BAND OF SILICON IN CROSSED ELECTRIC AND MAGNETIC-FIELDS

The Landau level structure of the degenerate valence band of silicon i n crossed electric and mag netic fields (B = 5 T, E = 0 to 5 kV cm(-1) ) has been calculated using the complete effective mass Hamiltonian fo r the three valence subbands. The calculations reveal a population inv ersion between light hole Landau levels at cryogenic temperatures due to a strongly level-dependent scattering on optical phonons, which is caused by quantum mechanical mixing of light and heavy hole states in crossed E and B fields. The possibility of amplification of far-infrar ed radiation on light hole cyclotron resonance transitions is discusse d.