Studies On Plasmon Characteristics In Semiconductor Symmetric Low Dimensional Quantum System

Properties of collective excitation in low-dimensional semiconductor structures have great practical application value, and become very important in the frontier re-search field in condensed matter physics now. For the past few years, this field received durable attention. In this thesis, we investiated intersubband collective excitation and single-particle excitation in semiconductor symmetric quantum well via numerical sim-ulation method.With the theory of numerical simulation between Schrodinger formula and Poisson formula, we got the electric potential and waves function of energy levels in a triangu-lar quantum well.In single-particle Hamilton eigenvector space, we derived dielectric function of semiconductor symmetric double quantum wells based on random-phase approximation (RPA) framework. In the two-subband model, we got some formulas which can determine the intrasubband and intersubband plasmon modes.By the result of numerical simulation of semiconductor symmetric quantum well, we found that energy of the intrasubband collictive excitation was much lower that energy of the intersubband collective excitation, the two branches were independent. Only if the wave vector increased up to a critical value, the intersubband collective excitations decayed into single-particle excitation region.