Engineering interaction effects in low-dimensional semiconductor nanostructures

如果不考虑电子-电子相互作用的作用，对低维电子系统中输运现象的全面理解是不完整的。目前研究的许多量子输运效应，例如0.7反常、维格纳结晶、库仑阻力和分数量子化，主要是由电子-电子相互作用主导的。因此，为了揭示相互作用在这种低维系统中的作用，必须引入新的方案来增强多体效应，然后这些多体效应可以被测量。增强相互作用效应的方法之一是利用高迁移率的二维电子气制备悬浮纳米结构。在这样的系统中，由于高介电常数薄膜中电场的部分限制和声子谱的改变，电子-电子相互作用得到增强。在这个研究项目中，博士生将加深对该领域的理解，并花费大量时间在洁净室中制造纳米级设备，用于详细的量子传输测量。他们将有机会参加与其博士项目直接相关的各种培训方案，如编程语言课程、低噪音电气测量和数据分析讲习班以及与行业建立联系的机会。学生将接受培训，如何使用高磁场的超低温稀释式制冷机在制造的纳米级设备上进行传输测量。它们将在强相互作用的悬浮和非悬浮、耦合量子点接触和量子线中进行输运，以研究新的基本量子物理，如非磁性分数态、自旋和电荷相，包括量子相变。目前的研究项目符合EPSRC的主题领域，如物理和工程科学以及量子技术。

A comprehensive understanding of the transport phenomena in low-dimensional electron systems is incomplete without considering the role of electron-electron interactions. Many of the currently studied quantum-transport effects, such as, for example, the 0.7-anomaly, Wigner crystallization, Coulomb drag and fractional quantisation, are largely dominated by electron-electron interactions. Thus, to reveal the role of interactions in such low-dimensional systems, novel schemes must be introduced to enhance many-body effects which can then be measured. One of the methods to enhance the interaction effects is to fabricate suspended nanostructures exploiting high mobility two-dimensional electron gas. In such systems, the electron-electron interactions get enhanced due to both partial confinement of electric field within a thin membrane having a high dielectric constant and modification of the phonon spectrum. In this research project, the PhD student will develop understanding of the field, and spend considerable time in the cleanroom fabricating nanoscale devices for detailed quantum transport measurement. They will have access to various training programmes directly related to their PhD project such as courses on programming languages, workshop on low-noise electrical measurements and data analysis as well opportunities for networking with industries. The student will be training on using ultra-low temperature dilution refrigerator with high magnetic field for performing transport measurement on the fabricated nanoscale devices. They will perform transport in strongly interacting suspended and non-suspended, coupled quantum point contacts and quantum wires to investigate new fundamental quantum physics such as the non-magnetic fractional states, spin and charge phases including quantum phase transition. The current research project is in line with the EPSRC thematic areas such as physical and engineering sciences and quantum technologies.