Topological Materials: Weyl Semimetals

Disordered Weyl Semimetals and Their Topological Family.

We develop a topological theory for disordered Weyl semimetals in the framework of the gauge invariance of the replica formalism and boundary-bulk correspondence of Chern insulators. An anisotropic topological θ term is analytically derived for the effective nonlinear σ model. It is this nontrivial topological term that ensures that the bulk transverse transport of Weyl semimetals is robust aga...

Helical Spin Order from Topological Dirac and Weyl Semimetals.

We study dynamical mass generation and the resultant helical spin orders in topological Dirac and Weyl semimetals, including the edge states of quantum spin Hall insulators, the surface states of weak topological insulators, and the bulk materials of Weyl semimetals. In particular, the helical spin textures of Weyl semimetals manifest the spin-momentum locking of Weyl fermions in a visible mann...

Multi-Weyl topological semimetals stabilized by point group symmetry.

We perform a complete classification of two-band k·p theories at band crossing points in 3D semimetals with n-fold rotation symmetry and broken time-reversal symmetry. Using this classification, we show the existence of new 3D topological semimetals characterized by C(4,6)-protected double-Weyl nodes with quadratic in-plane (along k(x,y)) dispersion or C(6)-protected triple-Weyl nodes with cubi...

Helicons in Weyl semimetals

Photocurrents in Weyl semimetals

Ching-Kit Chan,1 Netanel H. Lindner,2 Gil Refael,3 and Patrick A. Lee1 1Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA 2Physics Department, Technion, 320003 Haifa, Israel 3Institute of Quantum Information and Matter and Department of Physics, California Institute of Technology, Pasadena, California 91125, USA (Received 13 August 2016; revised m...