悬浮纳米管分子线中的负微分电导与热声子

Negative differential conductance and hot phonons in suspended nanotube molecular wires.

作者信息

Pop Eric, Mann David, Cao Jien, Wang Qian, Goodson Kenneth, Dai Hongjie

机构信息

Department of Chemistry and Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.

出版信息

Phys Rev Lett. 2005 Oct 7;95(15):155505. doi: 10.1103/PhysRevLett.95.155505.

DOI:10.1103/PhysRevLett.95.155505

PMID:16241738

Abstract

Freely suspended metallic single-walled carbon nanotubes (SWNTs) exhibit reduced current carrying ability compared to those lying on substrates, and striking negative differential conductance at low electric fields. Theoretical analysis reveals significant self-heating effects including electron scattering by hot nonequilibrium optical phonons. Electron transport characteristics under strong self-heating are exploited for the first time to probe the thermal conductivity of individual SWNTs (approximately 3600 W m-1 K-1 at T=300 K) up to approximately 700 K, and reveal a 1/T dependence expected for umklapp phonon scattering at high temperatures.

摘要

与置于基底上的金属单壁碳纳米管（SWNTs）相比，自由悬浮的金属单壁碳纳米管表现出较低的载流能力，并且在低电场下具有显著的负微分电导。理论分析揭示了显著的自热效应，包括热非平衡光学声子引起的电子散射。首次利用强自热条件下的电子输运特性，在高达约700K的温度下探测单个SWNTs的热导率（在T = 300K时约为3600W m-1 K-1），并揭示了高温下乌氏声子散射预期的1/T依赖性。