TY - DATA T1 - Generation of Anisotropic Massless Dirac Fermions and Asymmetric Klein Tunneling in Few-Layer Black Phosphorus Superlattices PY - 2017/02/23 AU - Zhenglu Li AU - Ting Cao AU - Meng Wu AU - Steven G. Louie UR - https://acs.figshare.com/articles/journal_contribution/Generation_of_Anisotropic_Massless_Dirac_Fermions_and_Asymmetric_Klein_Tunneling_in_Few-Layer_Black_Phosphorus_Superlattices/4718932 DO - 10.1021/acs.nanolett.6b04942.s001 L4 - https://ndownloader.figshare.com/files/7704793 KW - Few-Layer Black Phosphorus Superlattices KW - electron KW - chiral quasiparticles KW - wave packet incidence KW - massless Dirac fermions KW - phosphorus superlattices KW - Asymmetric Klein Tunneling KW - Anisotropic Massless Dirac Fermions KW - anisotropic 2 DEG KW - tunable anisotropic characteristics N2 - Artificial lattices have been employed in a broad range of two-dimensional systems, including those with electrons, atoms, and photons, in the quest for massless Dirac fermions with high flexibility and controllability. Establishing triangular or hexagonal symmetry, from periodically patterned molecule assembly or electrostatic gating as well as from moiré pattern induced by substrate, has produced electronic states with linear dispersions from two-dimensional electron gas (2DEG) residing in semiconductors, metals, and graphene. Different from the commonly studied isotropic host systems, here we demonstrate that massless Dirac fermions with tunable anisotropic characteristics can, in general, be generated in highly anisotropic 2DEG under slowly varying external periodic potentials. In the case of patterned few-layer black phosphorus superlattices, the new chiral quasiparticles exist exclusively in certain isolated energy window and inherit the strong anisotropic properties of pristine black phosphorus. These states exhibit asymmetric Klein tunneling, in which the transmission probability of the wave packets with normal incidence is no longer unity and can be tuned and controlled. In general, the direction of wave packet incidence for perfect transmission and that of the normal incidence are different, and the difference can reach more than 50° under an appropriate barrier orientation in black phosphorus superlattices. Our findings provide insight into the understanding and possible utilization of these novel emergent chiral quasiparticles. ER -