Quantum Interference Effects in Nanotransport

Quantum Interference Effects in Nanotransport

鄭鈞任(Chun-Jen Cheng)

指導教授 ： 林秀豪

國立清華大學/理學院/物理學系/碩士(2007年)

摘要

此論文以理論的角度研究奈米尺度下的傳輸現象。當傳輸的通道是以兩個能階表示時，傳輸過程中會發生量子干涉效應。

關鍵字

量子干涉 ； 量子效應 ； 奈米傳輸 ； 共振穿遂

並列摘要

This thesis is intended theoretically comparing the quantum properties through a single level to the transport through
the two levels in the 1D nanotransport. We use the tight-binding model and linearize the wave function of two leads. Meanwhile, we ignore the interaction between electrons, so the we deal with the 1D Fermi liquid without Coulomb blockade effect. We calculate these transport properties with equation of motion method and path integral method. Therefore, we conclude that the spectral function of a single level the get broadening when the levels are coupling to the leads which we regard as reservoirs. Besides, the Meir and Wingreen's formula is applied in a channel which is a single level, so that the conductance is proportional to the spectral function. However, when we consider the channel which is the two levels, the relation between the conductance and the spectral function is not
longer correct, that is because that there is quantum interference effects here.

並列關鍵字

quantum interference ； quantum effect ； nanotransport ； resonance tunneling

參考文獻

[1] B. J. van Wees et al., Quantized conductance of point contacts in a two-dimensional electron gas, Phys. Rev. Lett. 60, 848.

[2] Michael T. Woodside and Paul L. McEuen, Scanned Probe Imaging of Single-Electron Charge States in Nanotube Quantum Dots ,Science 296, 1098 (2002).

[3] P. Fallahi et al., Imaging a Single-Electron Quantum Dot, Nano Lett. 5, 223 (2005).

[4] B. J. van Wees et al., Quantum ballistic and adiabatic electron transport studies with quantum point contacts, Phys. Rev. B 43, 12431 (1991).

[5] C. L. Kane and Matthew P. A. Fisher, Transmission through barriers and resonant tunneling in an interacting one-dimensional electron gas, Phys. Rev. B, 46, 15233 (1992).