Low-Dimensional Phonon Phenomena in Nanometer Scale Structures

研究了横向尺寸小于声子主导波长的系统中电子和声子的输运性质。通常，这一标准在横向尺寸小于100nm且晶格温度低于1K的结构中得到满足。这些尺寸的导线将使用电子束技术在衬底上定义。为了避免衬底声子与导线模式之间耦合的影响，将使用蚀刻技术使结构独立。在足够低的温度下，他们期望观察到电线中声子的空间量子化，因此描述声子谱的维度相应减少。光谱的细节将通过研究比电子的非弹性散射长度短的金属线的电导变化来确定。在较长的导线中，磁导测量将用于研究声子和电子降维系统中的电子-声子相互作用。最后，他将研究独立介质线和半导体线中的声子散射过程和声子局部化效应。

The transport properties of electrons and phonons in systems with lateral dimensions less than the dominant phonon wavelength will be studied. Typically, this criterion is met in structures with lateral dimensions less than 100nm and at lattice temperatures below 1K. Wires of these dimensions will be defined on a substrate using electron-beam techniques. In order to avoid the effects of coupling between the substrate phonons and the modes of the wire, the structures will be made free-standing using etching techniques. At sufficiently low temperatures, they expect to observe spatial quantization of the phonons in the wires and so a commensurate reduction in the dimensionality describing the phonon spectrum. Details of the spectrum will be ascertained by studying the conductance variations of metallic wires that are shorter than the inelastic scattering length of the electrons. In longer wires, magneto-conductance measurements will be used to study the electron-phonon interaction in systems of reduced phonon and electron dimensionality. Finally, he will investigate phonon scattering processes and phonon localization effects in free-standing dielectric and semiconducting wires.