NER: Quantum Nanosensors Based on Controllable Electron-Phonon Coupling

该提案是针对NSE、NSF-0019而收到的。纳米传感器在表征大分子和生物对象、监测分子结合和控制量子点中的脱相过程等各种应用中都需要单个量子级别的灵敏度。在纳米结构中，声子交换太快，传感器与周围环境之间强烈的热(声子)耦合对普通测辐射热计传感器的灵敏度提出了严格的限制。在热电子传感器中，进入的量子只过热电子态，电子态由于电子-声子耦合而松弛到平衡。通过弱化电子与声子之间的有效耦合可以提高热电子传感器的灵敏度。在纳米导体中，与块体材料中的相互作用相比，电子-声子相互作用发生了实质性的改变。由于电子-声子和电子-边界散射的干涉，电子弛豫/退相速率很大程度上取决于边界的振动。它可以在很宽的范围内变化，跨越几个数量级，并且可以通过选择衬底材料来控制。提出的研究包括对超导纳米结构中电子散射机制之间的干扰进行复杂的研究，以及实验证明由边界和缺陷的弹性电子散射控制的电子能量弛豫，以及设计一种新的热电子传感器，其噪声等效功率的记录值为NEP=10-20W/Hz1/2，能量分辨率为5 10-24J，将能够计算单个低能量子(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).