Polar state of a particle with a degenerate band spectrum in a quantum dot

The energies of electron and hole polarons in spherical quantum dots based on materials with a high degree of ionicity are found. It is established th at consideration of the valence-band degeneracy causes the hole polaron bin ding energy to be greater than the electron polaron binding energy. The pol aron effects increase with decreasing quantum dot radius. Interband optical transitions are accompanied by partial compensation of the polaron effects , because the emergent electron and hole tend to create polarization potent ial wells with opposite signs. It is shown that complete compensation of th e polaron effects does not occur when the valence-band degeneracy is taken into account. Therefore, interband transitions are accompanied by polarizat ion of the medium. Such polarization is manifested by the appearance of a s eries of intense phonon replicas of the lines for the electronic transition s. (C) 1999 American Institute of Physics. [S1063-7826(99)01507-0].