A comparative study of magnetic (Mn) and non-magnetic (In) elements-doped Bi2Se3 topological insulator: Structural, magnetic, transport, and weak anti-localization property exploration

Abstract

The present comparative study explores the effect of magnetic (Mn) and non-magnetic (In) doping on structural, magnetic, and quantum-transport properties of Bi2Se3 topological insulator. Un-doped as well as Mn, In-doped Bi2Se3 samples have been synthesized using the solid-state reaction method, confirmed by HR-TEM results. The XRD pattern along with Rietveld refinement reveals that, both Mn and In-dopants substitute the Bi-ion together with slightly interstitially incorporation in host Bi2Se3. It is also found that In-doping is more preferable for Bi-substitution than Mn, which is well supported through our XPS analysis. The study of magnetism indicates the diamagnetic nature of un-doped Bi2Se3 gradually transformed into ferromagnetism for high Mn-doping, whereas In-doped Bi2Se3 shows a mixing of diamagnetism and paramagnetism. Electrical-transport establishes that In-doped Bi2Se3 preserves the hostʼs metallic nature; however, the arrest of metallic response is observed through the evidence of Kondo effect below 185 K for high Mn-doping. Interestingly, the Mn-doping creates a transformation of hostʼs weak anti-localization (WAL) towards weak localization (WL), and produces a significant reduction in the phase coherence length (lφ) of host Bi2Se3, verified by the magneto-conductance analysis. Whereas, In-doping shows relatively minor deviation in hostʼs WAL effect for higher doping limit.