Quantized Phonon Conductance of One-dimensional Systems

非技术摘要：固体的导电和导热能力决定了它在微电子等新技术中的应用潜力。令人惊讶的是，量子物理学预测，在纳米尺度下，固体的载电和载热能力不会随着横截面的减小而连续减小。这种量子理论已经在不同的实验中反复验证了不同纳米结构中电子的载电和载热能力。相比之下，在多晶氮化硅纳米结构中，只有一个报道的载热能力的预测量子行为的实验观察。为了响应对晶格热传输量子理论进行进一步实验研究的呼吁，该项目的重点是使用独特的测量方法对单个单壁碳纳米管中的量子理论进行实验研究。这项研究的成功预计将提高对凝聚态物理学重要支柱的理解，并为扩大参与量子和热科学研究和技术开发提供教育和宣传机会。 技术摘要：由于没有二能级缺陷，单壁碳纳米管在实验上实现的纳米结构中最接近理想的一维（1D）量子体系。这项工作的目标是推进1D纳米结构的本征热导的多探针测量，以准确检测在高达约10 K的相对较高的温度下预测的单壁碳纳米管的量子化声子电导。这个温度范围是更有利于产生明确的实验证据的量子化声子电导比低于-0.8 K的温度所需的氮化硅纳米梁先前的研究。如果成功，所提出的单壁碳纳米管测量将建立检测和控制低维系统量子化声子输运行为的实验能力。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical Abstract: The ability of a solid to conduct electricity and heat determines its application potential in new technologies such as microelectronics. Surprisingly, quantum physics predicts that the electricity- and heat- carrying capabilities of a solid at the nanometer scale do not reduce continuously with decreased cross-section. This quantum theory has been validated repeatedly in different experiments for both the electricity- and heat-carrying capabilities of electrons in different nanostructures. In comparison, there has been only one reported experimental observation of the predicted quantum behavior of the heat-carrying ability in a polycrystalline silicon nitride nanostructure. In response to a call for further experimental investigations of the quantum theory of lattice heat transport, this project is focused on experimental investigation of this quantum theory in individual single-walled carbon nanotubes with the use of a unique measurement method. Success of this research is expected to both enhance the understanding of a essential pillar of condensed matter physics and provide education and outreach opportunities for broadening the participation in quantum and thermal science research and technology developments. Technical Abstract: Free of two-level defects, SWCNTs are closest to an ideal one-dimensional (1D) quantum system among the nanostructures that have been experimentally realized. The goal of this work is to advance multiprobe measurements of the intrinsic thermal conductance of 1D nanostructures for accurate detection of the quantized phonon conductance that has been predicted for a SWCNT at a relatively high temperature up to about 10 K. This temperature range is much more conducive to producing unambiguous experimental evidence of quantized phonon conductance than the below-0.8 K temperature required for prior studies of silicon nitride nanobeams. If successful, the proposed measurements of SWCNTs will establish an experimental capability for detecting and controlling quantized phonon transport behaviors of low-dimensional systems. This capability is expected to advance the frontier of experimental research in a foundational area of condensed matter physics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.