Theoretical Study of Quantum Systems Interacting with a Phonon Bath.
Abstract
We have developed two complimentary theoretical approaches to study the dynamics of coupled electron-phonon systems. The first is based on coherent-state functional representations of ensemble averages and has been shown useful in the strong coupling limit of the electron-phonon coupling. A new exactly solvable model has been identified. A two level system coupled to phonons has been used to demonstrate irreversible dynamics. The second approach is based on non-equilibrium Green's functions which were used to derive Boltzmann-Bloch equations useful in the weak coupling limit. It has been used to discuss screening in such systems and to gain microscopic understanding of phase breaking in semiconductor systems. Specifically, the damping of charge oscillations and THz pulse emission has been studied for GaAs-AlGaAs double wells. Scattering theory has been developed for open mesoscopic electronic devices, formally exact in one dimension and heuristically for higher dimension. The signature of Bloch oscillations in the I-V characteristics of p-i-n diodes has been investigated. Exact open boundary conditions have been developed for the one-dimensional time-dependent Schrodinger equation and applied to a study of the dynamics of multi-barrier semiconductor heterostructures.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 22, 1996
- Accession Number
- ADA313791
Entities
People
- Walter Poetz
Organizations
- University of Illinois at Chicago