Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière , F-69622 , Villeurbanne , France.
Nano Lett. 2019 Mar 13;19(3):1534-1538. doi: 10.1021/acs.nanolett.8b04282. Epub 2019 Feb 11.
Mastering dissipation in graphene-based nanostructures is still the major challenge in most fundamental and technological exploitations of these ultimate mechanical nanoresonators. Although high quality factors have been measured for carbon nanotubes (>10) and graphene (>10) at cryogenic temperatures, room-temperature values are orders of magnitude lower (≃10). We present here a controlled quality factor increase of up to ×10 for these basic carbon nanostructures when externally stressed like a guitar string. Quantitative agreement is found with theory attributing this decrease in dissipation to the decrease in viscoelastic losses inside the material, an effect enhanced by tunable "soft clamping". Quality factors exceeding 25 000 for SWCNTs and 5000 for graphene were obtained on several samples, reaching the limits of the graphene material itself. The combination of ultralow size and mass with high quality factors opens new perspectives for atomically localized force sensing and quantum computing as the coherence time exceeds state-of-the-art cryogenic devices.
在基于石墨烯的纳米结构中掌握耗散仍然是大多数基础研究和技术应用这些终极机械纳谐振器的主要挑战。尽管在低温下已经测量到碳纳米管（>10）和石墨烯（>10）的高质量因数，但室温下的值要低几个数量级（≃10）。我们在这里展示了一种在外部应力下（如吉他弦）对这些基本碳纳米结构的可控质量因数增加高达×10 的方法。理论上定量的一致性将这种耗散的减少归因于材料内部粘弹性损耗的减少，这种效应通过可调“软夹”得到增强。在几个样品上获得了超过 25000 的 SWCNT 和 5000 的石墨烯的质量因数，达到了石墨烯材料本身的极限。超小尺寸和质量与高质量因数的结合为原子级局部力感应和量子计算开辟了新的前景，因为相干时间超过了最先进的低温设备。
