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arXiv · 1710.06238

Spectroscopic perspective on the interplay between electronic and magnetic properties of magnetically doped topological insulators

Jonas A. Krieger·Cui-Zu Chang·Marius-Adrian Husanu·Daria Sostina·Arthur Ernst·Mikhail M. Otrokov·Thomas Prokscha·Thorsten Schmitt·Andreas Suter·Maia Garcia Vergniory·Evgueni V. Chulkov·Jagadeesh S. Moodera·Vladimir N. Strocov·Zaher Salman
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Abstract

We combine low energy muon spin rotation (LE-$μ$SR) and soft-X-ray angle-resolved photoemission spectroscopy (SX-ARPES) to study the magnetic and electronic properties of magnetically doped topological insulators, (Bi,Sb)$_2$Te$_3$. We find that one achieves a full magnetic volume fraction in samples of (V/Cr)$_x$(Bi,Sb)$_{2-x}$Te$_3$ at doping levels x $\gtrsim$ 0.16. The observed magnetic transition is not sharp in temperature indicating a gradual magnetic ordering. We find that the evolution of magnetic ordering is consistent with formation of ferromagnetic islands which increase in number and/or volume with decreasing temperature. Resonant ARPES at the V $L_3$ edge reveals a nondispersing impurity band close to the Fermi level as well as V weight integrated into the host band structure. Calculations within the coherent potential approximation of the V contribution to the spectral function confirm that this impurity band is caused by V in substitutional sites. The implications of our results on the observation of the quantum anomalous Hall effect at mK temperatures are discussed.

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Jonas A. Krieger, Cui-Zu Chang, Marius-Adrian Husanu, Daria Sostina, Arthur Ernst, Mikhail M. Otrokov, Thomas Prokscha, Thorsten Schmitt, Andreas Suter, Maia Garcia Vergniory, Evgueni V. Chulkov, Jagadeesh S. Moodera, Vladimir N. Strocov, Zaher Salman. 2017-11-28. Spectroscopic perspective on the interplay between electronic and magnetic properties of magnetically doped topological insulators. https://doi.org/10.1103/physrevb.96.184402

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