机电学院学术报告： Exciton Dissociation by Topological Edge States

报告题目：Exciton dissociation by topological edge states/拓扑边缘态的激子解离

报告时间：2024年8月12日(周一) 10:00 AM

报告地点：青岛科技大学机电工程学院529报告厅

报告人：Dr. Udo Schwingenschlögl

Abstract /报告摘要：

Exciton dissociation by edge states can enhance the power conversion efficiency of solar cells. To evaluate the potential of this mechanism for carbon nanotubes as absorber material, we show that the topology of carbon nanotubes can be characterized by winding numbers related to the orbital angular momentum. The tight-binding Hamiltonian of any carbon nanotube with CN symmetry can be represented by N tight-binding Hamiltonians of decoupled molecular chains, for which a pseudospin formulation, characterized by specific paths in a two-dimensional auxiliary space, is developed. The quantum phases are given by the N winding numbers of these paths. The paths rotate in the auxiliary space when a magnetic field of varying strength is applied along the carbon nanotube, which gives rise to quantum phase transitions.

边缘态的激子解离可以提高太阳能电池的功率转换效率。为了评估这种机制在碳纳米管作为吸收材料方面的潜力，我们证明了碳纳米管的拓扑结构可以用与轨道角动量相关的缠绕数来表征。任何具有 CN 对称性的碳纳米管的紧束缚哈密顿都可以用 N 个解耦分子链的紧束缚哈密顿来表示。量子相位由这些路径的 N 个缠绕数给出。当沿碳纳米管施加不同强度的磁场时，这些路径会在辅助空间中旋转，从而产生量子相变。

Biography /报告人简介：

Udo Schwingenschlögl is a Professor of Solar Center at King Abdullah University of Science and Technology (KAUST). His research interests in condensed matter physics and first-principles materials modeling focus on two-dimensional materials, interface and defect physics, correlated materials, thermoelectric materials, metal-ion batteries, nanoparticles, and quantum transport. Unitl now, more than 400 related papers has been publised.

Udo教授是一名出色的理论模拟科学工作者，目前是沙特国王科技大学太阳能中心教授。他的研究兴趣主要包括材料模拟、第一性原理计算、新型功能材料、量子传输，二维材料和纳米材料。目前，他的相关研究成果已经发表400多篇SCI论文，其中包括PRL、AM、AEM等TOP杂志。