Influence of magnetic (Fe) and non-magnetic (In) doping on structural, magnetic, and weak anti-localization properties of Bi₂Te₃ topological insulator

Abstract

In this article, we have studied the changes in structural, magnetic, and magneto-transport properties of Bi2Te3 topological insulator doped with magnetic (Fe) as well as non-magnetic (In) elements. The un-doped along with Fe, In-doped Bi2Te3 are grown using a melt growth technique. The Rietveld analysis of x-ray diffraction data expresses that both In and Fe-dopants substituted the Bi-position with a little bit of interstitial incorporation in host Bi2Te3. It is also noticed that In-doping is slightly favorable for Bi-substitution than Fe. The magnetic characterization reveals a mixing of diamagnetic and Pauli paramagnetic behavior of un-doped and In-doped Bi2Te3, whereas, Fe-doping shows overall paramagnetism with local anti-ferromagnetic interactions among Fe-ions without long-range order. Electrical-transport study represents the metallic response of host Bi2Te3, which is well-maintained for In-doping; however, Fe-doping exhibits prominent anomalies in ρ_xx –T profiles. Importantly, magneto-conductance research indicates a notable deviation of host quantum feature, weak anti-localization effect (WAL) upon magnetic (Fe) doping, whereas non-magnetic In-doping shows a comparatively weak deviation in WAL effect for high doping limit.

DFT calculations of the structural, elastic, and electronic properties of (Bi1−xFex)2Te3 chalcogenides

“…Moreover, recently Kander et al [47] published an experimental article on Fe x Bi 2−x Se 3 with x = 0.1 and 0.4, at low concentration of Fe in Bi 2 Se 3 the dopant replaces Bi; whereas, at high concentration (x = 0.4) both substitution in Bi sites and intercalation in the host occurs [47]. Specifically, for Bi 2 Te 3 doped with Fe, small amounts of the dopant (x 0.2) generate magnetic properties at low temperature, weak ferromagnetism at T C = 14 K [48], higher concentrations of the dopant (8 %, x = 0.4) indicate that the dopant enters the structure in Bi sites and with interstitial incorporation of Fe [40]. Therefore, in this work a systematic study of the crystalline structure and mechanical, electronic properties of Bi 2 Te 3 with Fe as dopant in Bi sites with x = 0.0-0.2 is performed by first-principles calculations based on the density functional theory (DFT).…”

“…Fe is an element that has been used as a dopant in bismuth chalcogenides with the purpose of studying and modifying the magnetic properties in Bi 2 Se 3 and Bi 2 Te 3 [31][32][33][34][35][36]. Introducing magnetic atoms into bismuth chalcogenides can modulate the Fermi level in the exchange gap resulting in a quantum Hall effect at zero magnetic field [37], known as Quantum Anomalous Hall Effect [38][39][40], with other interesting effects, as the topological magnetoelectric effect [37], magneto-optical effect [41], allowing a new approach to develop electronic devices with a dissipation less edge transport in low-power electronic circuits to be applied in low- energy consumption spintronics and topological quantum computing [42]. However, the effect of Fe-doped on Bi 2 Te 3 for the study of mechanical and elastic properties has not been investigated.…”