Figure 2: Spectroscopic mapping of impurity-induced states.
From: Dual nature of magnetic dopants and competing trends in topological insulators
(a) Scanning tunnelling spectroscopy of the ferromagnetic Sb1.985V0.015Te3. Data have been acquired by positioning the tip away from any defect. The density of states reaches a minimum (see arrow) at ∼175 meV above the Fermi level. The spectra reveal the absence of any gap opening despite the existence of long-range ferromagnetic order (see zoomed area). Stabilization parameters: I=50 pA, V=450 mV, zoomed area I=50 pA, V=225 mV; (b,c) spectroscopic measurements taken along lines crossing the two different V sites (see insets). In both cases, strong resonances energetically located close to the Dirac point (indicated by BS) emerge in the nearby of the dopants; (d,e) spatial dependence of the dopants induced resonances for b,c, respectively. The zero in the distance axis corresponds to the position of maximum intensity. In both cases, the spectral weight decays over distances of few nanometres. T=4.8 K.
