Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 92: Topological Insulators I (jointly with MA, DS, HL, O)
TT 92.10: Talk
Thursday, March 19, 2015, 11:45–12:00, EB 202
Signatures of Dirac fermion-mediated magnetic order — •Paolo Sessi1, Felix Reis1, Thomas Bathon1, Konstantin Kokh2, Oleg Tereshchenko2, and Matthias Bode1 — 1Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany — 2Novosibirsk State University, 630090 Novosibirsk, Russia
The spin-momentum locking of topological states offers an ideal plat- form to explore novel magneto-electric effects. These intimately de- pend on the ability to manipulate the spin texture in a controlled way. Although numerous studies aimed to shed light on the role played by magnetic perturbations, contradictory results have been obtained and a clear picture is still missing. The interaction of surface magnetic moments with topological states has predominantly been performed by using spatial averaging techniques such as angle-resolved photoe- mission spectroscopy and x-ray magnetic circular dichroism. Here, we combine low-temperature scanning tunneling microscopy with single- adatom deposition to directly map the evolution of the electronic prop- erties of topological states under the influence of different magnetic perturbations. By analyzing energy-resolved quasi-particle interfer- ence maps, we reveal signatures of Dirac fermion-mediated surface magnetic order for extremely dilute adatom concentrations. By using different magnetic elements and coverages, we find that this striking observation crucially depends on two parameters: single adatoms mag- netic anisotropy direction and energy-level alignment [1].
[1] P. Sessi et al., Nature Comm. 5, 5349 (2014).