NM13.04.03 : Large Magnetic Gap at the Dirac Point in Mn-Doped Bi2Te3

5:00 PM–7:00 PM Apr 3, 2018 (America - Denver)

PCC North, 300 Level, Exhibit Hall C-E

Oliver Rader1

1, Helmholtz-Zentrum Berlin, Berlin, , Germany

Magnetic topological insulators enable the quantum anomalous Hall effect with edge states for lossless charge transport. These edge states are hosted by a magnetic band gap at the Dirac point which, however, never been observed directly by angle-resolved photoelectron spectroscopy (ARPES) despite its importance for the achievable operation temperature of devices. Here, ARPES is employed to demonstrate a magnetic gap at the Dirac point of Mn-doped Bi2Te3 films [1]. The gap is 32 meV wide [1] and thus twice as large as predicted by density functional theory [2]. We discuss reasons for this discrepancy. Moreover, the control system Mn-doped Bi2Se3 does not show a magnetic gap [3].

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[2] J. Henk, M. Flieger, I. V. Maznichenko, I. Mertig, A. Ernst, S. V. Eremeev, and E. V. Chulkov, Phys. Rev. Lett. 109, 076801 (2012)
[3] J. Sánchez-Barriga, A. Varykhalov, G. Springholz, H. Steiner, R. Kirchschlager, G. Bauer, O. Caha, E. Schierle, E. Weschke, A. A. Ünal, S. Valencia, M. Dunst, J. Braun, H. Ebert, J. Minár, E. Golias, L.V. Yashina, A. Ney, V. Holý, O. Rader, Nat. Commun. 7, 10559 (2016)