讲座题目：Exciton Dissociation by Topological Edge States

时间：8月14日上午10：00

地点：理学楼A301

报告人：Udo Schwingenschlögl教授

报告人简介：Dr. Schwingenschlögl is a Professor of Materials Science & Engineering 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. Dr. Schwingenschlögl joined KAUST as founding faculty member in 2008, having previously worked at the International Center of Condensed Matter Physics in Brasilia, Brazil, and the Universität Augsburg in Germany. Until now, more than 400 related papers have been published including Phys. Rev. Lett., Adv. Mater., and Adv. Energy Mater. etc.

讲座内容：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 C_Nsymmetry 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.

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理学院

2024年8月12日