title: Dual nature of magnetic dopants and competing trends in topological insulators.
abstract: Topological insulators interacting with magnetic impurities have been reported to host several unconventional effects. These phenomena are described within the framework of gapping Dirac quasiparticles due to broken time-reversal symmetry. However, the overwhelming majority of studies demonstrate the presence of a finite density of states near the Dirac point even once topological insulators become magnetic. Here, we map the response of topological states to magnetic impurities at the atomic scale. We demonstrate that magnetic order and gapless states can coexist. We show how this is the result of the delicate balance between two opposite trends, that is, gap opening and emergence of a Dirac node impurity band, both induced by the magnetic dopants. Our results evidence a more intricate and rich scenario with respect to the once generally assumed, showing how different electronic and magnetic states may be generated and controlled in this fascinating class of materials.
authors.affiliation: Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
authors.forename: Paolo
authors.initials: P
authors.lastname: Sessi
authors.affiliation: Department of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, Indiana 47907, USA.
authors.forename: Rudro R
authors.initials: RR
authors.lastname: Biswas
authors.affiliation: Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bathon
authors.affiliation: Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Storz
authors.affiliation: Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Wilfert
authors.affiliation: Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, 34149 Trieste, Italy.
authors.forename: Alessandro
authors.identifier: 0000-0002-5632-4915
authors.initials: A
authors.lastname: Barla
authors.affiliation: V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia.|Physics Department, Novosibirsk State University, 630090 Novosibirsk, Russia.|Physics Department, Saint-Petersburg State University, 198504 Saint-Petersburg, Russia.
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Kokh
authors.affiliation: Physics Department, Novosibirsk State University, 630090 Novosibirsk, Russia.|Physics Department, Saint-Petersburg State University, 198504 Saint-Petersburg, Russia.|A.V. Rzanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia.
authors.forename: Oleg E
authors.initials: OE
authors.lastname: Tereshchenko
authors.affiliation: Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.|Wilhelm Conrad Röntgen-Center for Complex Material Systems, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
authors.forename: Kai
authors.identifier: 0000-0001-6621-8860
authors.initials: K
authors.lastname: Fauth
authors.affiliation: Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.|Wilhelm Conrad Röntgen-Center for Complex Material Systems, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Bode
authors.affiliation: Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.|Nordita, Center for Quantum Materials, Department of Theoretical Physics, KTH Royal Institute of Technology, Stockholm University, Roslagstullsbacken 23, 106 91 Stockholm, Sweden.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Balatsky