Novel Anisotropic Dirac Materials: AMnBi2

• Speaker: Prof. Jun Sung Kim (POSTECH)
• Date: Wed Nov 27, 2015 17:00
• Place: Room 433 Asan Science

Dirac electronic structure, strong spin-orbit coupling, and magnetism are key elements for realizing various unconventional electronic states. Having these ingredients together in a single compound is extremely rare, and so far it has only been realized in a proximity-coupled interface of dissimilar layers having each property. In this talk, we report that a new layered compound AMnBi2 provide a natural heterostructure of a Bi layer hosting a two dimensional Dirac fermions with large spin-orbit coupling. Due to the underlying sublattice symmetry in the double-sized Bi square net, the Dirac Fermi surface has the strong momentum dependence of the in-plane Fermi velocity. By applying high magnetic field, we show that the strong anisotropy of the interlayer coupling induces a valley-selective conduction. Also, by introducing a magnetic layer, we show that the transport properties of Dirac fermions are strongly coupled to the underlying spin structure. These results clearly demonstrates that the Bi square net, a common building block of various layered pnictide compounds, is a new platform for a highly anisotropic Dirac fermions coupled to external or internal magnetic fields.