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arXiv 0810.1830cond-mat.mtrl-sci
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同位素无序碳纳米管中的热输运

Thermal transport in isotopically disordered carbon nanotubes

Gabriel Stoltz, Michele Lazzeri, Francesco Mauri

摘要:

本文研究了同位素无序碳纳米管的声子热导率。特别是,作为系统长度的函数的热导率的行为进行了研究,使用格林函数技术来计算整个系统的传输。该方法是使用线性缩放算法,这使我们能够达到系统的长度高达$L=2.5μ$ m(高达40万个原子)。对于1D系统,观察到电导率随系统尺寸$L$而发散。我们还观察到一个显着减少的实验尺寸的系统的热导率(约80%,在室温下为$L = 2.5$ $μ$ m),当引入了大部分的同位素无序。与格林函数技术得到的结果进行比较,得到的结果与玻尔兹曼描述的热传输。有一个很好的协议,这两种方法之间的系统的实验规模,即使在存在安德森局域化。这是特别有趣的,因为使用玻尔兹曼方程的传输的计算是少得多的计算昂贵的,使得更大的系统可以用这种方法进行研究。

英文摘要:

We present a study of the phononic thermal conductivity of isotopically disordered carbon nanotubes. In particular, the behavior of the thermal conductivity as a function of the system length is investigated, using Green's function techniques to compute the transmission across the system. The method is implemented using linear scaling algorithms, which allows us to reach systems of lengths up to $L=2.5μ$m (with up to 400,000 atoms). As for 1D systems, it is observed that the conductivity diverges with the system size $L$. We also observe a dramatic decrease of the thermal conductance for systems of experimental sizes (roughly 80% at room temperature for $L = 2.5$ $μ$m), when a large fraction of isotopic disorder is introduced. The results obtained with Green's function techniques are compared to results obtained with a Boltzmann description of thermal transport. There is a good agreement between both approaches for systems of experimental sizes, even in presence of Anderson localization. This is particularly interesting since the computation of the transmission using Boltzmann's equation is much less computationally expensive, so that larger systems may be studied with this method.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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