Collaborative research: Floquet-Bloch topological states in quantum Hall systems

摘要：本研究的目的是探索光诱导物质的新状态。该项目研究了这些状态的发生及其在连续光照下的操纵，使用了可以用可扩展工艺生长的原子薄材料，从而扩大了它们在新型设备上的潜在应用。研究团队希望这个项目能产生强大的教育影响：除了在pi的实验室里从事凝聚态物理的前沿研究外，研究生们还能接触到像国家强磁场实验室这样的世界级设施。该项目的牵头大学是一所西班牙裔服务机构，学生来自当地的美洲原住民部落，为推广工作提供了独特的机会。技术摘要：大量的晶体结构被预测为具有新的物质状态，这些状态由于其拓扑性质而具有鲁棒性，将它们与一个数字联系起来，即陈氏数，这是一个体积不变量，不受缺陷或样品形状的影响。因此，这些材料的大部分是绝缘的，表面是导电的，具有整数的反传播，自旋极化，无电阻，边缘电流模式，有望在拓扑低损耗电子和自旋电子学中应用。这个项目超越了晶体结构定义的拓扑材料，并解决了在没有这种边缘状态和拓扑琐碎的材料中诱导物质的拓扑状态的可能性。最近的理论预测，光可以作为拓扑开关，在一些原子薄的拓扑平凡材料中诱导拓扑保护的Floquet-Bloch边缘态。该项目研究了Floquet-Bloch边缘状态的生成，通过在稳态照明下驱动二维材料远离平衡，从而“按需”诱导拓扑状态。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical Abstract:The goal of this research is to investigate new states of matter induced by light. The project studies the occurrence of these states and their manipulation under continuous light illumination, using atomically thin materials that can be grown with scalable processes, thereby broadening their potential applications for novel devices. The research team expects a strong educational impact of the project: In addition to working on cutting-edge research in condensed matter physics in the PIs’ labs, graduate students are exposed to a world-class facility like the National High Magnetic Field Laboratory. The lead university in the project is a Hispanic Serving Institution, with students from local Native American tribes, providing unique opportunities for outreach efforts. Technical Abstract:A large number of crystal structures have been predicted to host novel states of matter that are robust due to their topological nature, linking them to a number, the Chern number, which is a bulk invariant, unaffected by defects or sample shape. As a result, the bulk of these materials is insulating and the surface is conducting, with an integer number of counter-propagating, spin-polarized, resistance-free, edge current modes holding promise for applications in topological low-loss electronics and spintronics. This project goes beyond the crystal-structure- defined topological materials and addresses the possibility of a topological state of matter being induced in a material that does not have such edge states and is topologically trivial. Recent theories predict that light can act as a topological switch to induce topologically protected Floquet-Bloch edge states in some atomically thin topologically trivial materials. This project studies the generation of Floquet-Bloch edge states by driving two-dimensional materials away from equilibrium with steady-state illumination, thereby inducing topological states “on demand”.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.