Structural and electronic transport properties of Zn- and Ga-doped Bi2-x Sb x Te3-y Se y topological insulator single crystals

Sanand Kumar Pradhan; Priyanath Mal; Sharadnarayan Pradhan; Archana Lakhani; Bipul Das; P Rambabu; G R Turpu; Pradip Das

doi:10.1088/1361-648X/ad43a7

Structural and electronic transport properties of Zn- and Ga-doped Bi_2-_x Sb _x Te_3-_y Se _y topological insulator single crystals

J Phys Condens Matter. 2024 May 9;36(31). doi: 10.1088/1361-648X/ad43a7.

Authors

Sanand Kumar Pradhan¹, Priyanath Mal², Sharadnarayan Pradhan¹, Archana Lakhani³, Bipul Das⁴, P Rambabu¹, G R Turpu¹, Pradip Das¹

Affiliations

¹ Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya, Koni, Bilaspur 495009, C.G., India.
² Department of Physics and Photon Science, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.
³ UGC-DAE CSR, University Campus, Khandwa Road, Indore 452001, India.
⁴ Department of Physics, National Taiwan Normal University, 162, section 1, Heping E. Rd., Taipei City 106, Taiwan.

PMID: 38663414
DOI: 10.1088/1361-648X/ad43a7

Abstract

A comprehensive study of structural and magnetotransport properties of pristine Bi_2-xSb_xTe_3-ySe_y(BSTS) single crystals and doped with Zn (BSTS:Zn) and Ga (BSTS:Ga) are presented here. Magnetic field dependent Hall resistivities of the single crystals indicate that the holes are the majority carriers. The field dependent resistivity curves at different temperatures of the crystals display cusp-like characteristics at low magnetic fields, attributed to two-dimensional (2D) weak antilocalization (WAL) effect. We fit the observed low-field WAL effects at low temperatures using 2D and three-dimensional (3D) Hikami-Larkin-Nagaoka (HLN) equations. The 2D HLN equation fits the data more closely than the 3D HLN equation, indicating a 2D nature. The 2D HLN equation fit to the low field WAL effects at various temperatures reveal a phase coherence length (l_φ) that decreases as temperature increases. The variation ofl_φwith temperature followsT^-0.41power law for BSTS:Zn, suggesting that the dominant dephasing mechanism is a 2D electron-electron (e-e) interactions. For pristine BSTS and BSTS:Ga,l_φ(T) is described by considering a coexistence of 2De-eand electron-phonon (e-p) interactions in the single crystals. The temperature variation of the longitudinal resistance in BSTS:Ga is described by 3D Mott variable range hoping model. In contrast, the transport mechanisms of both pristine BSTS and BSTS:Zn are described by a combination of 2D WAL/EEI models and 3D WAL.

Keywords: BSTS; single crystal; topological insulator; weak antilocalization effect.