Magnetotransport properties in a compensated semimetal gray arsenic

Lingxiao Zhao, Qiunan Xu, Xinmin Wang, Junbao He, Jing Li, Huaixin Yang, Yujia Long, Dong Chen, Hui Liang, Chunhong Li, Mianqi Xue, Jianqi Li, Zhian Ren, Li Lu, Hongmin Weng, Zhong Fang, Xi Dai, and Genfu Chen

Phys. Rev. B 95, 115119 – Published 10 March 2017

Abstract

We report the observation of an extremely large magnetoresistance (up to 15 000 000% at 1.8 K in a magnetic field of 9 T) in a simple chemical element, gray arsenic, in which the magnitude of the magnetoresistance increases as approximately the square of the magnetic field strength without any signs of saturation. The Hall-effect study confirms that gray arsenic is a nearly perfect “compensated semimetal,” with a small concentration of very mobile carriers, which lead to an extremely large magnetoresistance. The analysis of Shubnikov–de Haas oscillations reveals a nontrivial π Berry phase, a strong signature of Dirac fermions with three-dimensional dispersion. Furthermore, in the presence of parallel magnetic and electric fields, a weak antilocalization effect and a pronounced negative longitudinal magnetoresistance, which may be linked to novel topological states, are also observed. These findings which uncover the material's basis in gray arsenic not only open avenues in spintronics and magnetic sensor applications but also provide more platforms to study topological materials.

Received 19 October 2016
Revised 19 January 2017

DOI:https://doi.org/10.1103/PhysRevB.95.115119

Physics Subject Headings (PhySH)

Fermi surface Magnetotransport Semimetals Topological materials

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Lingxiao Zhao¹, Qiunan Xu¹, Xinmin Wang¹, Junbao He¹, Jing Li¹, Huaixin Yang¹, Yujia Long¹, Dong Chen¹, Hui Liang¹, Chunhong Li¹, Mianqi Xue¹, Jianqi Li^1,2,3, Zhian Ren^1,2,3, Li Lu^1,2,3, Hongmin Weng^1,2, Zhong Fang^1,2,3, Xi Dai^1,2,3,*, and Genfu Chen^1,2,3,†

¹Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
²School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
³Collaborative Innovation Center of Quantum Matter, Beijing 100190, China

^*daix@iphy.ac.cn
^†gfchen@iphy.ac.cn

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Vol. 95, Iss. 11 — 15 March 2017

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Images

Figure 1
(a) The crystal structure of α-As with $R \bar{3} m$ space group. (b) XRD pattern of α-As single crystal showing only $(00 l)$ reflections. (c) Temperature dependence of $ρ_{x x}$ under selected magnetic fields on log-log scale for sample 1. At low temperatures, $ρ_{x x}$ ( $B$ ) curves show the same character: After an initial rapid rise, $ρ_{x x}$ tends to saturate with a more distinct plateau. Inset: Plots of MR versus $B$ on logarithmic scales. (d) Magnetic field-dependent MR at various temperatures. Inset: The solid line shows the quadratic fit to the MR data at 1.8 K. (e) The derivative $\partial ρ / \partial T$ curves taken at several magnetic fields. Inset: $T_{m}$ and $T_{i}$ are determined as the temperatures at which the $\partial ρ / \partial T$ versus $T$ curves change sign and take a minimum. (f) Field dependence of $T_{m}$ and $T_{i}$ .
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Figure 2
(a) Hall resistivity $ρ_{x y}$ measured at several temperatures from 1.8 to 50 K. Inset: Magnetic field dependence of $σ_{x y}$ at 1.8 K. The solid line shows the best fitting with two-carrier model. (b) Temperature dependence of carrier density $n_{e}$ and $n_{h}$ . (c) Temperature dependence of carrier mobility $μ_{e}$ and $μ_{h}$ deduced by two-carrier model.
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Figure 3
(a) SdH oscillations in MR with the field applying along the trigonal axis at $T = 1.8 K$ . Upper inset: SdH oscillations in MR obtained by rotating the field away from the trigonal axis with angle of 15°. Lower inset: the corresponding measurement configurations. (b) The FFT spectra of the SdH oscillations. (c) Landau level index plots 1/ $B$ versus $n$ for the oscillation frequency of 187 T $(θ = 0^{\circ})$ . The purple circles are the maxima of the resistance and the red line is the linear fit. The initial Landau level only reaches to $n = 21$ in a magnetic field up to 9 T, far away from the quantum limit. Higher-magnetic-field experiments will be useful to approach the quantum limit to further confirm the existence of the nontrivial Berry phase. (d) Angular dependence of the SdH frequencies. The dashed lines are guides for the eyes. (e) The calculated FS topology. (f) The relationship between $k_{z}$ and the area of FS cut which is parallel to $k_{x} k_{y}$ surface. The origin is the central point of the Brillouin zone (BZ), and the dotted line demonstrates the edge of BZ.
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Figure 4
(a) Magnetoresistivity with rotating field from perpendicular $(θ = 0^{\circ})$ to parallel $(θ = 90^{\circ})$ to the electric current at 1.8 K (sample 2; the electric current flows along the bisectrix axis). The insets depict the corresponding measurement configurations. (b) The negative MR at $θ = 90^{\circ}$ (open circles) and fitting curve (red solid line) at 1.8 K for sample 2. (c) Magnetoresistance measured in different rotating angles around $θ = 90^{\circ}$ for sample 2. The negative MR appeared at a narrow region around $θ = 90^{\circ}$ , most obviously when $B$ // $I$ . (d) The MR data at $θ = 90^{\circ}$ (open circles) and fitting curves (dashed lines) at various temperatures for sample 2. (e) Magnetoresistivity with rotating field from perpendicular $(θ = 0^{\circ})$ to parallel $(θ = 90^{\circ})$ to the electric current at 1.8 K (sample 3; the electric current flows along the binary direction). The insets depict the corresponding measurement configurations. (f) The longitudinal MR measured at various temperatures for sample 3.
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