Ground state energy of a polaron in a superlattice

Abstract

The ground state energy of a polaron in a superlattice was calculated using the double-time Green functions. The effective mass of the polaron along the lanes perpendicular to the superlattice axis was also calculated. The dependence of the ground state energy and the effective mass along the lanes erpendicular to the superlattice axis on the electron–phonon coupling constant α and on the superlattice parameters (i.e. the superlattice period d and the and width 1) were studied. It was observed that if an infinite square-well potential is assumed, the ground state energy of the polaron decreases (i.e. becomes more negative) with increasing α and d, ut increases with increasing 1. For small values of α, the polaron ground state energy varies slowly with 1, becoming approximately constant for large 1. The effective mass along the lanes perpendicular to the superlattice axis was found to the approximately equal to the mass of an electron for all typical values of α, d and 1