中文摘要：

利用紧束缚格林函数和计算机数值模拟方法,研究了4种单壁碳纳米管分子异质结的相干输运性质。结果表明：（5,5）/（8,0）和（5,5）/（10,0）的金属/半导体型异质结局域态密度出现了新的量子态;金属/金属型异质结（5,5）/（9,0）A和（5,5）/（9,0）B的量子电导小于完好的碳纳米管,但局域态密度增大;金属/金属型异质结的量子电导对碳纳米管的连接方式表现敏感,当给定的两种金属碳纳米管连接时,不同连接方式的异质结可能是导体、半导体、绝缘体。

英文摘要：

Coherent transport properties of four kinds of molecular heterojunctions of single-walled car- bon nanotubes are studied by using the tight-binding green＇s function and computer numerical simulation meth- od. The calculation results show that, local state density of metal/semiconductor heterojunctions （5,5）/（8,0） composed of local density of states display appearance of new quantum states that allow electrons to pass through Quantum conductance of metal/heterojunctions （5,5）/（8,0） composed of metal is less than the intact carbon nanotubes, and the local state density increasedl Quantum conductance of metal/metal heterojunctions （5,5）/（9,0）A and （5,5）/（9,0）B are very sensitive to the linking manner of the carbon nanotubes, and when two given metallic carbon nanotubes are connected, heterojunctions formed in different liking manners may be conductors, semiconductors and insulators.