Crystal growth and magnetic structure of ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$

Crystal growth and magnetic structure of ${MnBi}_{2} {Te}_{4}$

J.-Q. Yan, Q. Zhang, T. Heitmann, Zengle Huang, K. Y. Chen, J.-G. Cheng, Weida Wu, D. Vaknin, B. C. Sales, and R. J. McQueeney

Phys. Rev. Materials 3, 064202 – Published 7 June 2019

Abstract

Millimeter-sized ${MnBi}_{2} {Te}_{4}$ single crystals are grown out of a Bi-Te flux and characterized using magnetic, transport, scanning tunneling microscopy, and spectroscopy measurements. The magnetic structure of ${MnBi}_{2} {Te}_{4}$ below $T_{N}$ is determined by powder and single-crystal neutron diffraction measurements. Below $T_{N}$ = 24 K, ${Mn}^{2 +}$ moments order ferromagnetically in the $a b$ plane but antiferromagnetically along the crystallographic $c$ axis. The ordered moment is 4.04(13) $μ_{B}$ /Mn at 10 K and aligned along the crystallographic $c$ axis in an A-type antiferromagnetic order. Below $T_{N}$ , the electrical resistivity drops upon cooling or when going across the metamagnetic transition in increasing magnetic fields. A critical scattering effect is observed in the vicinity of $T_{N}$ in the temperature dependence of thermal conductivity, indicating strong spin-lattice coupling in this compound. However, no anomaly is observed in the temperature dependence of thermopower around $T_{N}$ . Fine tuning of the magnetism and/or electronic band structure is needed for the proposed topological properties of this compound. The growth protocol reported in this work might be applied to grow high-quality crystals where the electronic band structure and magnetism can be finely tuned by chemical substitutions.

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Received 4 March 2019

DOI:https://doi.org/10.1103/PhysRevMaterials.3.064202

Physics Subject Headings (PhySH)

Antiferromagnetism Crystal growth Thermal conductivity Topological insulators

Magnetization measurements Neutron diffraction Resistivity measurements Scanning tunneling microscopy Scanning tunneling spectroscopy

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

J.-Q. Yan^1,*, Q. Zhang², T. Heitmann³, Zengle Huang⁴, K. Y. Chen⁵, J.-G. Cheng^5,6, Weida Wu⁴, D. Vaknin⁷, B. C. Sales¹, and R. J. McQueeney⁷

¹Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
²Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
³The Missouri Research Reactor, University of Missouri, Columbia, Missouri 65211, USA
⁴Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
⁵Beijing National Laboratory for Condensed Matter Physics and Institute of Physics,Chinese Academy of Sciences, Beijing 100190, China
⁶Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
⁷Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA