The magnetic response in a two-dimensional material has received increasing attention recent years. effects and related quantum transport originate from Berry curvature, which is associated with crystal symmetry many including electrons’ orbital magnetism, spin-orbit coupling, magnetoelectricity. importance of studying the lies two aspects. First, provides platform to investigate coupling betwe...

Chern number is usually characterized by Berry curvature. Here, investigating the Dirac model of even-dimensional insulator, we give general relation between curvature and quantum metric, which indicates that can be encoded in metric as well surface area Brillouin zone on hypersphere embedded Euclidean parameter space. We find there a corresponding relationship such hypersphere. geometrical pro...

Higgs spectroscopy, the study of bosons a superconductor, is an emerging field in studying superconductivity. Here we show that Berry curvature and quantum metric bands play central role mode generation. They allow detection even when conventional contribution from band vanishes. Furthermore, can couple to external electromagnetic linearly mediated by connection. As result, predict existence se...

Topological Weyl semimetals (WSMs) have been predicted to be excellent candidates for detecting Berry curvature dipole (BCD) and the related non-linear effects in electronics optics due large concentrated around nodes. And yet, linearized models of isolated tilted cones only realize a diagonal non-zero BCD tensor which sum zero model WSM with multiple nodes presence mirror symmetry. On other ha...

Jie Pan, Ting Zhang, Haijing Zhang, Bing Zhang, Zhen Dong, and Ping Sheng Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (Received 20 January 2017; revised manuscript received 2 June 2017; published 12 Septemb...

We derive the spin-wave dynamics of a magnetic material from the time-dependent spin-density-functional theory in the linear response regime. The equation of motion for the magnetization includes, besides the static spin stiffness, a "Berry curvature" correction and a damping term. A gradient expansion scheme based on the homogeneous spin-polarized electron gas is proposed for the latter two qu...

OF THE DISSERTATION Various Geometric Aspects of Condensed Matter Physics by Zhenyu Zhou Doctor of Philosophy in Physics Washington University in St. Louis, 2013 Professor Alexander Seidel, Chairperson Geometric aspect of condensed matter has arouse a lot of interests in recent years. The idea of Berry phase is highly appreciated in various systems. We explored the geometric features of two spe...

We predict that a temperature gradient can induce a magnon-mediated spin Hall response in an antiferromagnet with nontrivial magnon Berry curvature. We develop a linear response theory which gives a general condition for a Hall current to be well defined, even when the thermal Hall response is forbidden by symmetry. We apply our theory to a honeycomb lattice antiferromagnet and discuss a role o...

Topological physics is based on topological invariants such as the Chern number, which integral of Berry curvature. The quantum metric complementary to curvature in geometric tensor, but its role much less understood. authors show here that it becomes dominant for wave-packet dynamics at exceptional points strongly non-Hermitian systems. demonstrate that, thanks divergent metric, wave packets (...