NER: Quantum Nanosensors Based on Controllable Electron-Phonon Coupling

该提案是对NSE，NSF-0019的回应。 在单个量子的水平上的灵敏度是纳米传感器的各种应用所必需的，例如表征大分子和生物对象、监测分子结合以及控制量子点中的失相过程。 在纳米结构中，声子交换太快，并且传感器与其周围环境之间的强热（声子）耦合对普通测辐射热传感器的灵敏度提出了严格的限制。 在热电子传感器中，进入的量子仅使电子态过热，电子态由于电子-声子耦合而松弛到平衡。 热电子传感器的灵敏度可以通过削弱电子与声子之间的有效耦合来提高。 在纳米导体中，与体材料中的相互作用相比，电子-声子相互作用被显著地修改。由于电子-声子散射和电子-边界散射之间的干涉，电子弛豫/退相速率极大地依赖于边界的振动。 它可以在宽范围内变化，跨越几个数量级，并且可以通过选择衬底材料来控制。 拟议的研究包括超导纳米结构中电子散射机制之间的干扰的复杂调查和由边界和缺陷的弹性电子散射控制的电子能量弛豫的实验演示，以及具有噪声等效功率的创纪录值的新热电子传感器的设计，NEP=10- 20 W/Hz 1/2，和5 10- 24 J的能量分辨率，这将能够计数单个低能量子（光子或声子）。

This proposal was received in response to NSE, NSF-0019. Sensitivity at the level of individual quanta is required for such diverse applications of nanosensors as characterization of macromolecules and biological objects, monitoring of molecular binding, and control of dephasing processes in quantum dots. In nanoscale structures the phonon exchange is too fast, and strong thermal (phonon) coupling between the sensor and its surroundings puts strict limitations on the sensitivity of ordinary bolometric sensors. In the hot-electron sensor, the incoming quanta overheat only electron states, which relax to equilibrium due to electron-phonon coupling. The sensitivity of hot-electron sensors can be improved by weakening the effective coupling between electrons and phonons. In nanoconductors, the electron-phonon interaction is substantially modified in comparison with the interaction in bulk materials. Due to the interference between electron-phonon and electron-boundary scattering, the electron relaxation/dephasing rate depends drastically on vibrations of boundaries. It may vary over a wide range, spanning several orders of magnitude, and may be controlled by selection of a substrate material. The proposed research includes complex investigations of the interference between electron scattering mechanisms in superconducting nanostructures and experimental demonstration of the electron energy relaxation controlled by elastic electron scattering from boundaries and defects as well as the design of a new hot-electron sensor with a record value of the noise equivalent power, NEP=10-20W/Hz1/2, and the energy resolution of 5 10-24J, which will be able to count individual low-energy quanta (photons or phonons).