Manipulation of topological edge states

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Topological insulators (TIs) are materials that are insulating in the bulk but have conductive states at their edges, characterized by spin polarization and protection against non-magnetic perturbations. This book summarizes an experimental Ph.D. thesis focused on tailoring TIs for potential spintronic applications. The first section introduces the field and measurement techniques, specifically STM and ARPES. The second section details four experiments exploring various strategies to manipulate edge states. For the well-studied TI Bi2Se3, it is demonstrated that stoichiometric variations can enhance the edge state's isolation from the bulk band structure. Additionally, a method to introduce magnetic atoms (Fe) near the edge state without causing band bending is presented. Another experiment shows how creating a rough surface on TlBiSe2 can shift its edge state into the bulk. Lastly, growing a Bi bilayer on Bi2Se3 is shown to further move the edge state outward, allowing interaction with bilayer states. These experiments confirm the topological nature of the edge states and highlight their implications. The manipulation techniques discussed may pave the way for tailoring TIs for future technologies leveraging spin degrees of freedom.