Superparamagnetism-induced mesoscopic electron focusing in topological insulators
Sessi, Paolo (Universität Würzburg)
Rüßmann, P. (Peter Grünberg Institut)
Bathon, Thomas (Universität Würzburg)
Barla, Alessandro (Consiglio Nazionale Delle Ricerche)
Kokh, K. A. (Novosibirsk State University)
Tereshchenko, O. E. (Russian Academy of Sciences)
Fauth, Kai (Universität Würzburg)
Mahatha, Sanjoy K (Consiglio Nazionale Delle Ricerche)
Valbuena, Miguel Ángel (Institut Català de Nanociència i Nanotecnologia)
Godey, Sylvie (Institut Català de Nanociència i Nanotecnologia)
Glott, F. (Physikalisches Institut. Experimentelle Physik II. Universität Würzburg)
Mugarza, Aitor (Institut Català de Nanociència i Nanotecnologia)
Gargiani, Pierluigi (ALBA Laboratori de Llum de Sincrotró)
Valvidares, Manuel (ALBA Laboratori de Llum de Sincrotró)
Long, N. H. (Peter Grünberg Institut)
Carbone, Carlo (Consiglio Nazionale Delle Ricerche)
Mavropoulos, Phivos (Peter Grünberg Institut)
Blügel, Stefan (Peter Grünberg Institut)
Bode, Matthias (Universität Würzburg)

Additional title:	Mesoscopic electron focusing in topological insulators
Date:	2016
Abstract:	Recently it has been shown that surface magnetic doping of topological insulators induces backscattering of Dirac states which are usually protected by time-reversal symmetry [Sessi, Nat. Commun. 5, 5349 (2014)10. 1038/ncomms6349]. Here we report on quasiparticle interference measurements where, by improved Fermi level tuning, strongly focused interference patterns on surface Mn-doped Bi2Te3 could be directly observed by means of scanning tunneling microscopy at 4 K. Ab initio and model calculations reveal that their mesoscopic coherence relies on two prerequisites: (i) a hexagonal Fermi surface with large parallel segments (nesting) and (ii) magnetic dopants which couple to a high-spin state. Indeed, x-ray magnetic circular dichroism shows superparamagnetism even at very dilute Mn concentrations. Our findings provide evidence of strongly anisotropic Dirac-fermion-mediated interactions and demonstrate how spin information can be transmitted over long distances, allowing the design of experiments and devices based on coherent quantum effects in topological insulators.
Grants:	Ministerio de Economía y Competitividad MAT2013-46593-C6-5-P Ministerio de Economía y Competitividad SEV-2013-0295 Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-715
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió sotmesa a revisió
Published in:	Physical review B, Vol. 94, Issue 7 (August 2016) , art. 75137, ISSN 2469-9969

DOI: 10.1103/PhysRevB.94.075137

Preprint 15 p, 5.7 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Catalan Institute of Nanoscience and Nanotechnology (ICN2)
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > The ALBA Synchrotron
Articles > Research articles
Articles > Published articles