Epitaxial growth, magnetoresistance, and electronic band structure of GdSb magnetic semimetal films

Inbar, Hadass S., Ho, Dai Q., Chatterjee, Shouvik, Pendharkar, Mihir, Engel, Aaron N., Dong, Jason T., Khalid, Shoaib, Chang, Yu Hao, Guo, Taozhi, Fedorov, Alexei V., Lu, Donghui, Hashimoto, Makoto, Read, Dan ORCID: https://orcid.org/0000-0002-4178-4986, Janotti, Anderson and Palmstrøm, Christopher J. 2022. Epitaxial growth, magnetoresistance, and electronic band structure of GdSb magnetic semimetal films. Physical Review Materials 6 (12) , L121201. 10.1103/PhysRevMaterials.6.L121201

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Abstract

Motivated by observations of extreme magnetoresistance (XMR) in bulk crystals of rare-earth monopnictide (RE-V) compounds and emerging applications in novel spintronic and plasmonic devices based on thin-film semimetals, we have investigated the electronic band structure and transport behavior of epitaxial GdSb thin films grown on III-V semiconductor surfaces. The Gd 3 + ion in GdSb has a high spin S = 7 / 2 and no orbital angular momentum, serving as a model system for studying the effects of antiferromagnetic order and strong exchange coupling on the resulting Fermi surface and magnetotransport properties of RE-Vs. We present a surface and structural characterization study mapping the optimal synthesis window of thin epitaxial GdSb films grown on III-V lattice-matched buffer layers via molecular-beam epitaxy. To determine the factors limiting XMR in RE-V thin films and provide a benchmark for band-structure predictions of topological phases of RE-Vs, the electronic band structure of GdSb thin films is studied, comparing carrier densities extracted from magnetotransport, angle-resolved photoemission spectroscopy (ARPES), and density-functional theory (DFT) calculations. ARPES shows a hole-carrier rich, topologically trivial, semimetallic band structure close to complete electron-hole compensation, with quantum confinement effects in the thin films observed through the presence of quantum-well states. DFT-predicted Fermi wave vectors are in excellent agreement with values obtained from quantum oscillations observed in magnetic field-dependent resistivity measurements. An electron-rich Hall coefficient is measured despite the higher hole-carrier density, attributed to the higher electron Hall mobility. The carrier mobilities are limited by surface and interface scattering, resulting in lower magnetoresistance than that measured for bulk crystals.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy
Publisher:	American Physical Society
ISSN:	2475-9953
Date of First Compliant Deposit:	13 March 2024
Date of Acceptance:	20 October 2022
Last Modified:	14 Mar 2024 14:03
URI:	https://orca.cardiff.ac.uk/id/eprint/166234

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