Origin of linear magnetoresistance in Bi2Te3 topological insulator: Role of surface state and defects

• Published in: Physica. B, Condensed matter Condensed matter, 2024-04, Vol.679, p.415801, Article 415801
• Main Authors: Rana, Nabakumar, Singha, Pintu, Mukherjee, Suchandra, Das, Subarna, Das, Gangadhar, Deb, Apurba Kanti, Chakravarty, Sujay, Bandyopadhyay, S., Banerjee, Aritra
• Format: Article
• Language: English
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2024.415801

Connection between topological surface states (TSS) and large linear magnetoresistance (LMR) is established in tetradymite Bi2Te3 through tuning of native defects. Thorough analysis of temperature dependent synchrotron X-ray diffraction data quantifies 0-D, 1-D and 2-D defect concentrations. Plausible variation of antisite defects is explained via carrier concentration data. Resistivity data divulge contribution of mixed bulk and surface states in the synthesized samples. High Fermi velocity (∼106 ms−1) and low Fermi energy (∼14 meV) of carriers are obtained. Lower defect concentration sample emerges with high magnetoresistance (MR) and higher mobility. Weak antilocalization (WAL) effect, signature of TSS, is revealed from MR. Large (80%), non-saturating LMR along with ultrahigh mobility (∼1 m2V−1s−1) in Bi2Te3 supports the presence of TSS. Magnetoconductance data are fitted with Hikami-Larkin-Nagaoka equation, obtaining further insight on WAL effect. In addition, extracted parameters like disorder correlation length and coherence length explicate the role of defect density on LMR.