Coupling of 2D plasmons to nonlocal bulk plasmons

• Published in: Physica. B, Condensed matter Vol. 299; no. 1; pp. 165 - 172
• Main Authors: Horing, Norman J.M., Gumbs, Godfrey, Park, Tae-ik
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.05.2001; Elsevier
• Subjects: 2D plasmons; 3D plasmons; Collective excitations (including excitons, polarons, plasmons and other charge-density excitations); Collective excitations (including plasmons and other charge-density excitations); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Mode-coupling; Nonlocality; Physics; Quantum wells; Surface and interface electron states; 73.50.Mx; 73.20.Mf; 78.66.−w; Mode-coupling; 3D plasmons; Nonlocality; 2D plasmons; 71.35.Lk; Continuum; Dielectric function; Dimensionality; Semiconductor materials; Dispersion relations; Quantum wells; Theoretical study; Coupled modes; Plasmons; Response functions; Heterostructures; Non local theory
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/S0921-4526(00)00585-8

An explicit closed-form position-space expression for the highly inhomogeneous inverse dielectric response function of a quantum well (QW) of finite width (with a single bound subband state) embedded in a bulk medium having a continuum of extended states is derived here analytically. The resulting position-dependent nonlocal dynamic inverse dielectric function ε −1(z,z′; q ||, ω) , given in position representation for the z-direction across the well, depends on the in-plane wave vector q || and frequency ω as well as on the positional variables z, z′. Spatial inhomogeneity arises from the lack of translational invariance in the z-direction due to the presence of the QW. The frequency poles of ε −1(z,z′; q ||, ω) obtained here represent the coupling of nonlocal bulk plasmons with two-dimensional (2D) intrasubband plasmons of the QW. The dispersion relation of the coupled modes is examined. The bulk particle–hole modes damp the collective excitations of the coupled 2D and bulk systems and we estimate the damping rate.