Unconventional Unidirectional Magnetoresistance in vdW Heterostructures

Fuente: arXiv
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Main Authors: Kao, I-Hsuan, Tang, Junyu, Ortiz, Gabriel Calderon, Zhu, Menglin, Yuan, Sean, Rao, Rahul, Li, Jiahan, Edgar, James H., Yan, Jiaqiang, Mandrus, David G., Watanabe, Kenji, Taniguchi, Takashi, Hwang, Jinwoo, Cheng, Ran, Katoch, Jyoti, Singh, Simranjeet
Format: Preprint
Published: 2024
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author Kao, I-Hsuan
Tang, Junyu
Ortiz, Gabriel Calderon
Zhu, Menglin
Yuan, Sean
Rao, Rahul
Li, Jiahan
Edgar, James H.
Yan, Jiaqiang
Mandrus, David G.
Watanabe, Kenji
Taniguchi, Takashi
Hwang, Jinwoo
Cheng, Ran
Katoch, Jyoti
Singh, Simranjeet
author_facet Kao, I-Hsuan
Tang, Junyu
Ortiz, Gabriel Calderon
Zhu, Menglin
Yuan, Sean
Rao, Rahul
Li, Jiahan
Edgar, James H.
Yan, Jiaqiang
Mandrus, David G.
Watanabe, Kenji
Taniguchi, Takashi
Hwang, Jinwoo
Cheng, Ran
Katoch, Jyoti
Singh, Simranjeet
contents Electrical readout of magnetic states is a key to realize novel spintronics devices for efficient computing and data storage. Unidirectional magnetoresistance (UMR) in bilayer systems, consisting of a spin source material and a magnetic layer, refers to a change in the longitudinal resistance upon the reversal of magnetization, which typically originates from the interaction of spin-current and magnetization at the interface. Because of UMR s linear dependence on applied charge current and magnetization, it can be used to electrically read the magnetization state. However, in conventional spin source materials, the spin polarization of an electric field induced spin current is restricted to be in the film plane and hence the ensuing UMR can only respond to the in plane component of the magnetization. On the other hand, magnets with perpendicular magnetic anisotropy (PMA) are highly desired for magnetic memory and spin-logic devices, while the electrical read out of PMA magnets through UMR is critically missing. Here, we report the discovery of an unconventional UMR in bilayer heterostructures of a topological semimetal (WTe2) and a PMA ferromagnetic insulator (Cr2Ge2Te6, CGT), which allows to electrically read the up and down magnetic states of the CGT layer by measuring the longitudinal resistance. Our theoretical calculations based on a tight binding model show that the unconventional UMR originates from the interplay of crystal symmetry breaking in WTe2 and magnetic exchange interaction across the WTe2 and CGT interface. Combining with the ability of WTe2 to obtain magnetic field free switching of the PMA magnets, our discoveries open an exciting pathway to achieve two terminal magnetic memory devices that operate solely on the spin orbit torque and UMR, which is critical for developing next-generation non volatile and low power consumption data storage technologies.
format Preprint
id arxiv_https___arxiv_org_abs_2405_10889
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Unconventional Unidirectional Magnetoresistance in vdW Heterostructures
Kao, I-Hsuan
Tang, Junyu
Ortiz, Gabriel Calderon
Zhu, Menglin
Yuan, Sean
Rao, Rahul
Li, Jiahan
Edgar, James H.
Yan, Jiaqiang
Mandrus, David G.
Watanabe, Kenji
Taniguchi, Takashi
Hwang, Jinwoo
Cheng, Ran
Katoch, Jyoti
Singh, Simranjeet
Mesoscale and Nanoscale Physics
Materials Science
Electrical readout of magnetic states is a key to realize novel spintronics devices for efficient computing and data storage. Unidirectional magnetoresistance (UMR) in bilayer systems, consisting of a spin source material and a magnetic layer, refers to a change in the longitudinal resistance upon the reversal of magnetization, which typically originates from the interaction of spin-current and magnetization at the interface. Because of UMR s linear dependence on applied charge current and magnetization, it can be used to electrically read the magnetization state. However, in conventional spin source materials, the spin polarization of an electric field induced spin current is restricted to be in the film plane and hence the ensuing UMR can only respond to the in plane component of the magnetization. On the other hand, magnets with perpendicular magnetic anisotropy (PMA) are highly desired for magnetic memory and spin-logic devices, while the electrical read out of PMA magnets through UMR is critically missing. Here, we report the discovery of an unconventional UMR in bilayer heterostructures of a topological semimetal (WTe2) and a PMA ferromagnetic insulator (Cr2Ge2Te6, CGT), which allows to electrically read the up and down magnetic states of the CGT layer by measuring the longitudinal resistance. Our theoretical calculations based on a tight binding model show that the unconventional UMR originates from the interplay of crystal symmetry breaking in WTe2 and magnetic exchange interaction across the WTe2 and CGT interface. Combining with the ability of WTe2 to obtain magnetic field free switching of the PMA magnets, our discoveries open an exciting pathway to achieve two terminal magnetic memory devices that operate solely on the spin orbit torque and UMR, which is critical for developing next-generation non volatile and low power consumption data storage technologies.
title Unconventional Unidirectional Magnetoresistance in vdW Heterostructures
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2405.10889