B20 compounds, such as MnSi, FeGe, and FeCoSi, are series of magnetic materials with the lowest symmetry in cubic crystal systems. These reduced symmetries host abundant phases and physical properties, among which the appearance of magnetic skyrmion is the most exciting discovery in these materials. A magnetic skyrmion is a topologically non-trivial spin texture in which local magnetic moments point in all directions wrapping a sphere. It is characterized by a nonvanishing topological charge, which gives rise to novel features that are absent in any other topological trivial textures.
In this talk, I will discuss the unconventional magnetoresistance from broken rotational symmetry, and the properties of magnetic skyrmions induced by broken inversion symmetry. New approach to create skyrmion and emergent gauge field will be presented, which are closely related to the topological charge. Interplay between the magnon and skyrmion will be discussed, and physics of skyrmion rotations is investigated.
Jiadong Zang is currently the postdoctoral fellow in the institute for quantum matter, Johns Hopkins University. He received his B. Sc. in Physics from Fudan University in 2007, and Ph.D in Physics from Fudan University in 2012. He was a visiting student at the University of Tokyo in 2009. He joined Johns Hopkins in August 2012. His principal research field is theoretical condensed matter physics, with special emphasis on topological aspects (such as topological spin texture, topological insulator, and quantum spin models). He is recently focusing on the skyrmions in helimagnets, and interplay between spin-orbital interaction and strong correlations.