Quantum transport, bifurcations, and emergent dynamic phases in strongly driven nanostructures

本理论项目解决了辐照二维电子系统低温磁输运中两种引人注目的非平衡现象：微波诱导电阻振荡（MIRO）和相关的零电阻状态（ZRS）。最近自发电压的时间分辨测量为ZRS的域性质提供了第一个直接证据。同时，这些实验揭示了缓慢的时间动力学（包括序参数的自振荡和极性相反的畴构型之间的近周期性切换），这是现有理论预测静态畴所无法预料的。最近，首席研究员提出了一种可以合理解释ZRS丰富动力学的慢动力学机制，并将在本项目中进行全面研究。与领先的实验小组的共同努力，有望在了解几种竞争的动态和静态ZRS机制方面取得重大进展。虽然直到最近，MIRO和ZRS仅在高迁移率的AlGaAs/GaAs异质结构中观察到，但新的实验技术，如局部脉冲太赫兹激光激发以及快速的技术进步，使得它们在几种不同的材料体系（目前包括p型Si/SiGe， ZnO/MnZnO和液体He表面的电子）中观察到它们成为可能。在这个方向上进一步结合理论和实验研究应该：(1)区分这些现象的普遍属性和依赖于材料/几何的属性；（ii）建立观察的一般条件；（三）阐明仍然存在争议的问题，例如MIRO惊人的极化免疫；（iv）提供无法从标准运输测量中获得的材料参数。

This theoretical project addresses two spectacular nonequilibrium phenomena in the low-temperature magnetotransport of irradiated two-dimensional electron systems: microwave-induced resistance oscillations (MIRO) and associated zero resistance states (ZRS). Recent time-resolved measurements of spontaneous voltages provided first direct evidence for the domain nature of ZRS. At the same time, these experiments revealed slow temporal dynamics (including self-oscillations of the order parameter and the regime of nearly periodic switching between domain configurations of the opposite polarity) not expected from the existing theory predicting static domains. A mechanism of slow dynamics that gives a plausible explanation for the rich dynamics of ZRS was recently proposed by the principal investigator and will be comprehensively studied in this project. Joint efforts with leading experimental groups promise significant advances in the understanding of several competing dynamic and static regimes of the ZRS. While until recently MIRO and ZRS were only observed in high-mobility AlGaAs/GaAs heterostructures, novel experimental techniques such as local pulsed terahertz-laser excitation as well as rapid technological advances made feasible their observation in several different material systems (currently including p-type Si/SiGe, ZnO/MnZnO, and electrons on surface of liquid He). Further combined theoretical and experimental studies in this direction should (i) provide a distinction between universal and material/geometry dependent properties of these phenomena; (ii) establish generic conditions for their observation; (iii) shed light on remaining controversial issues such as the striking polarization immunity of MIRO; (iv) provide access to the material parameters not accessible from standard transport measurements.