报告题目: Berry phase effects on Bloch electrons in electromagnetic fields

    报告人: Qian Niu(牛谦)教授 University of Texas at Austin and ICQM at PKU

    时间: 2013年11月11日(星期一) 上午10:00

    地点: 中国科学院半导体研究所 图书馆101会议室

    Abstract: Berry curvature and orbital moment of the Bloch state are two basic ingredients, in addition to the band energy, that must be included in the formulation of semiclassical dynamics of electrons in crystals, in order to give proper account of thermodynamic and transport properties to first order in the electromagnetic field. These quantities are gauge invariant and have direct physical significance as demonstrated by numerous applications in recent years. Generalization to the case of degenerate bands has also been achieved, with important applications in spin-dependent transport. We have now extended the theory to second order in electromagnetic fields, keeping the structure of the first order theory but greatly expanding the scope of applications. I will illustrate two applications of the extended theory, magneto polarization and nonlinear anomalous Hall effects.

    Biography: 牛谦教授1981年毕业于北京大学物理系。 1981年考取第一批CUSPEA赴美国留学，1985年获得美国华盛顿大学博士学位，现为美国University of Texas奥斯丁分校物理系的Trull Centennia讲席教授。1999年因对量子输运理论的突出贡献，成为美国物理学会Fellow。牛谦教授在凝聚态物理理论方面论著甚丰，影响很大，已发表SCI收录论文165篇， 其中包括PRL论文54篇, Science 论文2篇, Nature, PhysicsToday和Physics World论文各1篇，他引达到5千多次；论文引用的H因子达到40，在国内外学术会议上作邀请报告160多次。牛谦教授在量子论、凝聚态物理等方面具有很深的造诣，在相关的研究领域引领世界科学研究的潮流，在超冷原子、自旋电子学以及将几何相位引入到凝聚态物理中等方面做出了重要工作，是国际上著名的物理学家，也是为数不多的、活跃在前沿物理研究中的杰出华人科学家代表。