Engineering and probing topological properties of Dirac semimetal films by asymmetric charge transfer
5 oktober 2016
UAntwerpen, Campus Groenenborger, Building U, room U.241 - Groenenborgerlaan 171 - 2020 Antwerpen (route: UAntwerpen, Campus Groenenborger
16 - 17 uur
Organisatie / co-organisatie:
Condensed Matter Theory group
Physics Department seminar presented by Prof Kyungwha Park from Virginia Tech University
Dirac semimetals (DSMs) have topologically robust three-dimensional (doubled Weyl) nodes with Fermi-arc states. In heterostructures involving DSMs, charge transfer may occur at the interfaces, which can be used to probe and control their bulk and surface topological properties through surface-bulk connectivity. We demonstrate that despite a band gap in DSM films, asymmetric charge transfer at the surface enables one to accurately identify locations of the Dirac-node projections from gapless band crossings and to examine and engineer properties of the topological Fermi-arc surface states connecting the projections, by simulating adatom-adsorbed DSM films using a first-principles method with an effective model. The positions of the Dirac-node projections are insensitive to charge transfer amount or slab thickness except for extremely thin films. By varying the amount of charge transfer, unique spin textures near the projections and a separation between the Fermi-arc states change, which can be observed by gating without adatoms.
Physics department seminar presented by Prof. Kyungwha Park from Virginia Tech University, USA.
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