报告人：牛谦 教授 The University of Texas at Austin
报告题目：Berry phase effects on charge and spin transport
报告摘要：Ever since its discovery, the notion of Berry phase has permeated through all branches of physics. Over the last three decades, it was gradually realized that the Berry phase of the electronic wave function can have a profound effect on material properties and is responsible for a spectrum of phenomena, such as polarization, orbital magnetism, various (quantum/anomalous/spin) Hall effects, and quantum charge pumping. This is revealed most clearly in the semiclassical formulation of electron dynamics, which is a versatile tool in the study of electron dynamics in the presence of electromagnetic fields and more general perturbations. I will also demonstrate a re-quantization method that converts a semiclassical theory to an effective quantum theory. It is clear that the Berry phase should be added as an essential ingredient to our understanding of basic material properties.