The Bounded Polaronic Effect In Quantum Well

The thesis concerns mainly about the bounded polaronic effect in the parabolic quantum well in an electric field.In the first chapter of this thesis, we introduce the conception of polaron and simply review the progress of the polaronic theory. Then we reduce the theoretic base, the Frohlich continuum polaronic Hamiltonian. At the same time, we show the importance of the polaronic effect especially in quantum well, in the research of theory and experience as well.In the second chapter, we divide the polaron into two kinds by the coupling constant. One is big polaron and the other is small polaron. We mainly discuss the big polaron. Because there exists the different strength of coupling between the electron and phonon, there have some different ways, such as the perturbation theory, variation theory, Green function theory and the Feynman' s path integral approach. They can be appropriately used in different area. At last, we introduce the conception of bound polaron.The single bounded polaronic Hamiltonian are gotten by the Pekar' s theory.The third chapter is the main work. We discuss how to deal with the polaronic effect by the Feynman path integral. It' s fit for the polaronic models of all coupling strength. We creatively apply this way to the bounded polaron in the parabolic quantum well and get the analytical expressions of the ground state energy of an electron bound to a hydrogenic impurity in a parabolic quantum well in an electric field. We found that the polaronic effects and electric field effects have significant contributions to the ground state energy. Some numerical results about the relations between the ground state energy and the Coulomb binding parameter, the parabolicity parameter, and electric field strength are obtained. Our results can reduce to some well known results in the limiting case of bulk material without electric field. In the end, we discuss the promising perspective and the problems in dealing with the polaronic question in complex quantum well. By the way of development in the numerical technique, such as Quantum Monte Carlo Method, the Feynman path approach wilt play greater roles.