  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.
