Geometric valley Hall effect and valley filtering through a singular Berry flux

Hong-Ya Xu,1 Liang Huang,2 Danhong Huang,3,4 and Ying-Cheng Lai1,5,* 1School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287, USA 2School of Physical Science and Technology, and Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou, Gansu 730000, China 3Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117, USA 4Center for High Technology Materials, University of New Mexico, 1313 Goddard St SE, Albuquerque, New Mexico 87106, USA 5Department of Physics, Arizona State University, Tempe, Arizona 85287, USA (Received 16 August 2016; revised manuscript received 12 June 2017; published 12 July 2017)