Browsing by Author "Yang, Shengyuan A."
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Item Chirality-Dependent Hall Effect in Weyl Semimetals(Amer Physical Soc, 2015-10-09) Yang, Shengyuan A.; Pan, Hui; Zhang, Fan; School of Natural Sciences and Mathematics; 0000-0003-4623-4200 (Zhang, F); Zhang, FanWe generalize a semiclassical theory and use the argument of angular momentum conservation to examine the ballistic transport in lightly doped Weyl semimetals, taking into account various phase-space Berry curvatures. We predict universal transverse shifts of the wave-packet center in transmission and reflection, perpendicular to the direction in which the Fermi energy or velocities change adiabatically. The anomalous shifts are opposite for electrons with different chirality, and they can be made imbalanced by breaking inversion symmetry. We discuss how to utilize local gates, strain effects, and circularly polarized lights to generate and probe such a chirality-dependent Hall effect.Item Circular Dichroism and Radial Hall Effects in Topological Materials(Amer Physical Soc, 2018-10-22) Liu, Ying; Yang, Shengyuan A.; Zhang, Fan; 0000-0003-4623-4200 (Zhang, F); Zhang, FanUnder symmetry breaking, a three-dimensional nodal-line semimetal can turn into a topological insulator or Weyl semimetal, accompanied by the generation of momentum-space Berry curvature. We develop a theory that unifies their circular dichroism and highlights the roles of Berry curvature distribution and light incident direction. Nontrivially, these phases exhibit distinct dichroic optical absorption and radial Hall effects, with characteristic scalings with photon energy and electric field. Our findings offer a diagnosis tool for examining topological phases of matter.Item Perfect Valley Filter in a Topological Domain Wall(Amer Physical Soc, 2015-07-07) Pan, Hui; Li, Xin; Zhang, Fan; Yang, Shengyuan A.; Zhang, FanWe propose a realization of perfect valley filters based on the chiral domain-wall channels between a quantum anomalous Hall insulator and a quantum valley Hall insulator. Uniquely, all these channels reside in the same valley and propagate unidirectionally, 100% valley-polarizing passing-by carriers without backscattering. The valley index, the chirality, and the number of the channels are protected by topological charges, controllable by external fields, and detectable by circular dichroism.