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

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

Publication Type:

Journal Article

Source:

Physical Review B, Volume 96, Issue 18 (2017)

ISBN:

2469-9950

Abstract:

<p>We combine low energy muon spin rotation (LE-mu 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 greater than or similar to 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.</p>