Regensburg 2016 – scientific programme

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O: Fachverband Oberflächenphysik

O 77: Gerhard Ertl Young Investigator Award

O 77.4: Invited Talk

Thursday, March 10, 2016, 12:00–12:30, S051

Visualizing topological states of matter and their interaction with perturbations using local probes — •Paolo Sessi — Universität Würzburg

Topological insulators (TIs) are a new class of materials insulating in the bulk but conductive on their surface where they host linearly dispersing gapless Dirac states. The strong spin-orbit coupling perpendicularly locks the spin to the momentum, leads to a chiral spin texture that restricts scattering channels, and results in spin currents intrinsically tied to charge currents. Since all these properties manifest at surfaces, scanning probe techniques are ideal tools to visualize them with both high spatial and energy resolution. In my talk, I will present a series of experiments that allow not only to visualize the presence of Dirac boundary modes, but also to directly prove some of their most remarkable properties. In particular, I will discuss recent efforts focused onto the controlled manipulation of topological states, which is achieved by coupling TIs to well-defined perturbations. First, I will demonstrate that surface magnetic doped TIs can establish magnetic order at very dilute concentrations. Then, I will report on the realization of spin networks of different symmetries conveniently created at TI surfaces by self-assembly processes. Finally, I will illustrate how the introduction of strain can be successfully used to engineer TI transport properties.