单壁碳纳米管的电极耦合效应研究

利用紧束缚格林函数和计算机数值模拟方法，研究了单壁碳纳米管的电极耦合效应．计算结果表明，电极耦合强度直接影响系统的量子电导：在电极和中心单壁碳纳米管之间无耦合作用时，系统的行为呈现出理想的电导量子化特征，电导呈台阶式增长，最小电导为4e2/h； 在电极和中间单壁碳纳米管之间处于强耦合作用时，系统像个Fabry—Perot电子谐振腔，表现出明显的量子电导快速振荡和背景缓慢振荡；而对于耦合较弱的情况，由于电子在界面处所受散射作用的增强，系统的电导降低；当耦合作用极其微弱时，系统达到量子电导振荡的极限，像个量子点，此时电子在输运过程中只能一个接一个地通过碳纳米管．

Study on the Electrical Contacts Coupling Effect on Single-Walled Carbon Nanotube

The electrical contacts coupling effect on a left lead/central single-walled carbon nanotubes/ right lead system is studied by using the tight binding Green function approach. The conclusion showes that at ideal coupling strength between electrical contact and central SWNT, the quantum conductance of the system goes up as steps at strong coupling strength between electrical contact and central SWNT, the system behaves as Fabry-Perot electron resonator, which can show distinct quantum conductance oscillations and complicate background as the Fermi energy is driven by the gate-voltage Vg, the shape of conductance strength, the system presents well defined resonant peaks, which is the limit of the quantum background is de- contacts coupling conductance oscillations.