Discovery of several large families of Topological Insulator classes with backscattering-suppressed spin-polarized single-Dirac-cone on the surface

TL;DR

This paper reports the theoretical prediction and experimental discovery of new classes of topological insulators with large surface gaps and diverse surface states, advancing materials for spintronics and quantum computing.

Contribution

The authors identify several new topological insulator classes with large gaps and tunable surface states, expanding the range of materials for quantum applications.

Findings

Discovery of new topological insulator classes with gaps up to 0.35 eV

Observation of diverse surface dispersion and spin textures

Potential platforms for topological-superconductivity research

Abstract

Three dimensional (3D) topological insulators are novel states of quantum matter that feature spin-momentum locked helical Dirac fermions on their surfaces and hold promise to open new vistas in spintronics, quantum computing and fundamental physics. Experimental realization of many of the predicted topological phenomena requires finding multi-variant topological band insulators which can be multiply connected to magnetic semiconductors and superconductors. Here we present our theoretical prediction and experimental discovery of several new topological insulator classes in AB2X4(124), A2B2X5(225), MN4X7(147), A2X2X'(221) [A,B=Pb,Ge,Sb,Bi and M,N=Pb,Bi and X,X'=Chalcogen family]. We observe that these materials feature gaps up to about 0.35eV. Multi-variant nature allows for diverse surface dispersion tunability, Fermi surface spin-vortex or textured configurations and spin-dependent electronic interference signaling novel quantum transport processes on the surfaces of these materials. Our discovery also provides several new platforms to search for topological-superconductivity (arXiv:0912.3341v1 (2009)) in these exotic materials.