Dissertation > Excellent graduate degree dissertation topics show

Theoretical Study on Quantum Transport Properties of Multi-Treminal Coupled-Quantum-Dot Systems

Author: YinYongZuo
Tutor: WangXuanZhang
School: Harbin Normal University
Course: Condensed Matter Physics
Keywords: Quantum dots Quantum Transport Annular array Tunneling probability
CLC: O471.1
Type: Master's thesis
Year: 2010
Downloads: 42
Quote: 0
Read: Download Dissertation

Abstract

The movement of electrons in the quantum dot system coherence mesoscopic electronic transport properties of the basic physical mechanisms. The multi-quantum dot system for electron tunneling wear to provide more coherent path (ie Feynman path), study the coupling of electron transport properties of the quantum dot system, reveal the resonance and anti-resonance tunneling both quantum coherent phenomena, for nano- the design and manufacture of the devices provide a theoretical basis. Attention so that people will be transferred directly to the discrete structure up due to the miniaturization of electronic devices in the future. In this thesis, the non-equilibrium Green's function as a theoretical tool, the theoretical study of the electronic transport properties of multi-terminal quantum dot molecules bridge and four quantum dots ring bypass coupled quantum dot tandem array system, which specifically includes: multiport coupling quantum transport properties of the quantum dot molecule bridge. Non-equilibrium Green's function equations of motion and the Dyson equation, the system tunneling current expression. Given by numerical calculation of the system is decoupled into two terminal, three-terminal and four-terminal case, the tunneling coefficient I1α between the electrode and the other electrode (omega) in a variety of single quantum dot level combination coupling strength between the quantum dots for different values ??of the calculated results, and the results obtained were compared and analyzed. Studies have shown that: Electronic wear chance of tunneling through the molecular bridge the oscillation structure; electronic wear chance electrode energy of the electrons tunnel through the closely related; When exist suspension quantum dots, if the electrode electronic energy levels of quantum dot level alignment, there will be \Bypass of two coupled quantum dot array terminal quantum dot ring system electronic transport properties were studied. The transmission characteristics of the system bypass coupled quantum dot array parity dependence of the number of quantum dots, as well as the ring and bypass coupling array of quantum dots quantum dot level does not match, the law of the anti-resonance tunneling sex. The value of the tunneling probability, studies show that: exactly match the single quantum dot level, due to the bypass coupled quantum dot tandem array, the tunneling line slightly more than both sides ε0 ± 2V0 range and at the ε0 the obvious parity characteristics dependencies bypass coupled quantum dot array contains an odd number of quantum dots, the anti-resonance appears. Ring quantum dot level is not equal to the energy level of the quantum dots and quantum dot array, the parity characteristics disappear. On the contrary, if the array is the number of quantum dots and rings coupled with the array of quantum dots and is a multiple of 3, the anti-resonance. If the coupling strength between adjacent quantum dots are different, the number of tunneling spectroscopy in resonant states and anti-resonance tunneling zero did not change, but with the difference of the coupling strength different coupling configuration on the energy spectrum of the system characterized in there is still a very important role.

Related Dissertations

CLC: > Mathematical sciences and chemical > Physics > Semiconductor physics > Semiconductive Theory > Semiconductor quantum theory
© 2012 www.DissertationTopic.Net Mobile