Giant tunneling magnetoresistance induced by bias voltage in spin-filter van der Waals magnetic tunnel junctions with an interlayer antiferromagnetic semiconductor barrier

Xiaoyan Guo, Baishun Yang, Xiaolin Zhang, Yu Zhu, Xiufeng Han, and Yu Yan

Phys. Rev. B 104, 144423 – Published 25 October 2021

Abstract

Spin-filter van der Waals Magnetic tunnel junctions (sf-vdW MTJs) formed by an interlayer antiferromagnetic (AFM) vdW semiconductor as a barrier have exhibited promising prospects in achieving a high tunneling magnetoresistance (TMR) ratio in MTJs. Here, using first-principles calculations, we investigate the spin-dependent transport and the TMR effect of sf-vdW MTJs formed by sandwiching bilayer and trilayer $Ni {Br}_{2}$ barriers between two graphite electrodes ( $Gr / Ni {Br}_{2} / Gr$ sf-vdW MTJs). Similar to the experimental results of sf-vdW MTJs formed by a few-layer $Cr I_{3}$ barrier, the TMR ratios of the $Gr / Ni {Br}_{2} / Gr$ sf-vdW MTJs increase first with the increase of bias voltage and decrease with the further increase of bias voltage after reaching the highest points because the conduction bands of the interlayer ferromagnetic (FM) $Ni {Br}_{2}$ barrier at the $K$ points go into the bias window earlier than those of the interlayer AFM $Ni {Br}_{2}$ barrier with the increase of bias voltage. Compared to the TMR ratios of about 170% and 206% at zero bias voltage, the TMR ratios of the $Gr / Ni {Br}_{2} / Gr$ sf-vdW MTJs with bilayer and trilayer $Ni {Br}_{2}$ barriers are largely increased about 34 and 67 times by the optimized bias voltage, respectively. Correspondingly, a giant TMR ratio of about 6000% and 14 000% can be achieved in the $Gr / Ni {Br}_{2} / Gr$ sf-vdW MTJs with bilayer and trilayer $Ni {Br}_{2}$ barriers at 0.14 and 0.125 V bias voltage, respectively. Our results elucidate the mechanism of bias voltage induced giant TMR ratio in the $Gr / Ni {Br}_{2} / Gr$ sf-vdW MTJs and provide promising routes for developing MTJs with a high TMR ratio.

Received 13 May 2021
Revised 11 September 2021
Accepted 11 October 2021

DOI:https://doi.org/10.1103/PhysRevB.104.144423

Physics Subject Headings (PhySH)

Magnetic order Quantum transport Spintronics

Antiferromagnets Magnetic semiconductors Magnetic tunnel junctions

First-principles calculations Nonequilibrium Green's function

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Xiaoyan Guo¹, Baishun Yang², Xiaolin Zhang¹, Yu Zhu^1,3, Xiufeng Han³, and Yu Yan ^1,*

¹Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), Department of Physics, Jilin University, Changchun 130012, China
²Shenzhen JL Computational Science and Applied Research Institute, Shenzhen 518109, China
³Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China

^*yanyu@jlu.edu.cn

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand

Issue

Vol. 104, Iss. 14 — 1 October 2021

Reuse & Permissions

Access Options

Author publication services for translation and copyediting assistance advertisement

Images

Figure 1
(a) Top view of monolayer $Ni {Br}_{2}$ and (b) side view of bulk $Ni {Br}_{2}$ . (c) Top view of the interface between graphene and $Ni {Br}_{2}$ in the $Gr / Ni {Br}_{2} / Gr$ heterostructures. (d) Side views of the $Gr / Ni {Br}_{2} / Gr$ sf-vdW MTJs with bilayer and trilayer $Ni {Br}_{2}$ barriers, respectively.
Reuse & Permissions
Figure 2
Band structure of the interlayer (a) FM and (e) AFM bilayer $Ni {Br}_{2}$ . Band structure of the $Gr / Ni {Br}_{2} / Gr$ heterostructure when bilayer $Ni {Br}_{2}$ is the interlayer (b) FM and (f) AFM states. Red and black curves represent the majority- and minority-spin bands. Local (c), (g) majority- and (d), (h) minority-spin DOSs in the real space along the transport direction of the $Gr / Ni {Br}_{2} / Gr$ heterostructure when bilayer $Ni {Br}_{2}$ is the interlayer (c), (d) FM and (g), (h) AFM states, respectively. The Fermi energy is indicated by the horizontal dashed line.
Reuse & Permissions
Figure 3
Band structure of the interlayer (a) FM and (e) AFM trilayer $Ni {Br}_{2}$ . Band structure of the $Gr / Ni {Br}_{2} / Gr$ heterostructure when trilayer $Ni {Br}_{2}$ is the interlayer (b) FM and (f) AFM states. Red and black curves represent the majority- and minority-spin bands. Local (c), (g) majority- and (d), (h) minority-spin DOSs in the real space along the transport direction of the $Gr / Ni {Br}_{2} / Gr$ heterostructure when trilayer $Ni {Br}_{2}$ is the interlayer (c), (d) FM and (g), (h) AFM states, respectively. The Fermi energy is indicated by the horizontal dashed line.
Reuse & Permissions
Figure 4
Total currents of the $Gr / Ni {Br}_{2} / Gr$ MTJs as a function of bias voltage when (a) bilayer and (b) trilayer $Ni {Br}_{2}$ are the interlayer FM and AFM states and TMR ratios of the $Gr / Ni {Br}_{2} / Gr$ MTJs as a function of bias voltage.
Reuse & Permissions
Figure 5
Total transmission coefficients of the $Gr / Ni {Br}_{2} / Gr$ sf-vdW MTJs with (a), (b) bilayer and (c), (d) trilayer $Ni {Br}_{2}$ barriers as a function of energy at different bias voltages. Red and black curves represent the transmission coefficients when the bilayer and trilayer $Ni {Br}_{2}$ barriers are the interlayer FM and AFM states, respectively. The gray shadows represent the bias window. The Fermi energy is indicated by the vertical dashed line.
Reuse & Permissions
Figure 6
Band structures around the $K$ points of the $Gr / Ni {Br}_{2} / Gr$ sf-vdW MTJs with (a), (b) bilayer and (c), (d) trilayer $Ni {Br}_{2}$ barriers at different bias voltages when bilayer and trilayer $Ni {Br}_{2}$ are the interlayer (a), (c) FM and (b), (d) AFM states, respectively. The red and black curves represent the majority- and minority-spin bands. The gray shadows represent the bias window. The Fermi energy is indicated by the horizontal dashed line.
Reuse & Permissions

Physical Review B

covering condensed matter and materials physics