Tunable Casimir equilibria with phase change materials: From quantum trapping to its release
Tunable Casimir equilibria with phase change materials: From quantum trapping to its release
复制标题
相变材料的可调谐卡西米尔平衡：从量子捕获到量子释放
DOI：
10.1103/physrevb.101.104107
复制
发表时间：
2020-03-31
影响因子：
3.7
通讯作者：
Gong, Ke
中科院分区：
文献类型：
--
作者：
Ge, Lixin;Shi, Xi;Gong, Ke
由于Casimir力的作用，纳米粒子的稳定悬浮在传感、非接触纳米机械等许多应用中具有重要意义。然而，器件一旦制造出来，悬浮性就很难改变。二氧化钒(VO$2)是一种相变材料，它在340K左右经历了从低温绝缘相到高温金属相的转变。在这项工作中，我们研究了纳米板(金或特氟龙)与含有VO$2薄膜的层状结构之间的Casimir力。结果表明，在液体环境中可以实现纳米板稳定的Casimir悬浮液，其平衡距离不仅取决于膜的厚度，还取决于VO$2的物相。在适当的设计下，揭示了由于VO$2$从金属到绝缘体的转变，金纳米板的量子陷阱(“开”态)到其释放(“关”态)的转变。另一方面，在VO$2的绝缘体到金属的跃迁下，发现了聚四氟乙烯纳米板的量子捕获和释放。我们的发现为设计用于微纳机电系统的可切换器件提供了可能性。
A stable suspension of nanoscale particles due to the Casimir force is of great interest for many applications such as sensing, non-contract nano-machines. However, the suspension properties are difficult to change once the devices are fabricated. Vanadium dioxide (VO$_2$) is a phase change material, which undergoes a transition from a low-temperature insulating phase to a high-temperature metallic phase around a temperature of 340 K. In this work, we study Casimir forces between a nanoplate (gold or Teflon) and a layered structure containing a VO$_2$ film. It is found that stable Casimir suspensions of nanoplates can be realized in a liquid environment, and the equilibrium distances are determined, not only by the layer thicknesses but also by the matter phases of VO$_2$. Under proper designs, a switch from quantum trapping of the gold nanoplate ("on" state) to its release ("off" state) as a result of the metal-to-insulator transition of VO$_2$, is revealed. On the other hand, the quantum trapping and release of a Teflon nanoplate is found under the insulator-to-metal transition of VO$_2 $. Our findings offer the possibility of designing switchable devices for applications in micro-and nano-electromechanical systems.