Efficient charge-spin conversion and magnetization switching through the Rashba effect at topological-insulator/Ag interfaces

Shi, Shu; Wang, Aizhu; Wang, Yi; Ramaswamy, Rajagopalan; Shen, Lei; Moon, Jisoo; Zhu, Dapeng; Yu, Jiawei; Oh, Seongshik; Feng, Yuanping; Yang, Hyunsoo

doi:10.1103/physrevb.97.041115

Cited by 58 publications

(50 citation statements)

References 53 publications

(88 reference statements)

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“…On the other hand, a number of emerging 2D crystals and topological materials are promising platforms for spintronics [ 15,16 ] due to their large intrinsic SOC and nontrivial spin textures. [ 17–19 ] In addition, crystal symmetries can be explored to engineer charge‐to‐spin conversion and SOT in device configurations that have been so far inaccessible.…”

Section: Figurementioning

confidence: 99%

Spin‐Orbit Torque Magnetization Switching in MoTe₂/Permalloy Heterostructures

et al. 2020

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The ability to switch magnetic elements by spin‐orbit‐induced torques has recently attracted much attention for a path toward high‐performance, nonvolatile memories with low power consumption. Realizing efficient spin‐orbit‐based switching requires the harnessing of both new materials and novel physics to obtain high charge‐to‐spin conversion efficiencies, thus making the choice of spin source crucial. Here, the observation of spin‐orbit torque switching in bilayers consisting of a semimetallic film of 1T′‐MoTe2 adjacent to permalloy is reported. Deterministic switching is achieved without external magnetic fields at room temperature, and the switching occurs with currents one order of magnitude smaller than those typical in devices using the best‐performing heavy metals. The thickness‐dependence can be understood if the interfacial spin‐orbit contribution is considered in addition to the bulk spin Hall effect. Further threefold reduction in the switching current is demonstrated with resort to dumbbell‐shaped magnetic elements. These findings foretell exciting prospects of using MoTe2 for low‐power semimetal‐material‐based spin devices.

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Section: Figurementioning

confidence: 99%

Spin‐Orbit Torque Magnetization Switching in MoTe₂/Permalloy Heterostructures

et al. 2020

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“…Compared to Bi 2 Se 3 , intrinsic defects were suppressed in Bi 2 S 3 under both cation-and anion-poor growth conditions. [88] In addition, first-principles calculations for a Bi 2 Se 3 /Ag/CoFeB system showed how a coexistence of topological surface states and the Rashba effect contributed to the enhanced charge-to-spin conversion in that system, [205] which was recently observed in spintorque ferromagnetic resonance measurement.…”

Section: Topology and Structurementioning

confidence: 80%

Advances in Functional Nanomaterials Science

Rahimi‐Iman

2020

Annalen der Physik

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Technologies employing nanomaterials, such as electronics, optoelectronics, nanobiotechnologies, quantum optics, and nanophotonics, are perceived as the key drivers of investigations on novel and functional materials and their nanostructures for various applications. It is well understood that the study of such materials and structures has been of great importance for the optimization and development of electrical and optical devices. From such devices, one does not only expect higher efficiencies, but also access to the development of completely new concepts, which are strongly demanded by modern information‐processing, quantum, or medical technologies, and sensing applications. In this context, a wide range of aspects such as the physics of novel materials, as well as materials engineering, characterization, and applications are summarized here. Novel materials, which can be used, for instance, for energy harvesting or light generation, as well as for future logic devices; material engineering, which can lead to improved device functionality and performance in optoelectronics; material physics, the study of which allows insight to be gained into optical and electrical properties of nanostructured systems and quantum materials; and technologies/devices, addressing progress on the application side of sophisticated material systems and quantum structures, are highlighted using representative examples.

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“…Since the spin-injection and transport mechanisms are the same for the two samples, it is possible to quantitatively compare the results obtained with Bi 2 Se 3 and Pt detectors. were performed to characterize the spin-to-charge conversion in Bi 2 Se 3 thin films [8][9][10] and, at variance with our result, the conversion parameter was always measured with the same sign as ISHE in Pt, which we arbitrarily define as "positive." Although the SCC measurements in Refs.…”

Section: Nonlocal Spin-to-charge Conversion Measurementsmentioning

confidence: 85%

“…In these systems, the leading parameters are the spin-charge interconversion efficiencies: q REE = j 3D s / j 2D c for the REE and λ IREE = j 2D c / j 3D s for the IREE. However, an experimental estimation based on spin pumping-ferromagnetic resonance (FMR) or spin torque-FMR [8][9][10] is questionable, since TIs are known to chemically react when they are in contact with a ferromagnetic film [11,12]. Therefore, a nonlocal architecture where the source of the spin current and the TI are well separated would represent a reliable route to avoid the aforementioned issue.…”

Section: Introductionmentioning

confidence: 99%

Spin orbitronics at a topological insulator-semiconductor interface

et al. 2020

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Topological insulators (TIs) hold great promise for new spin-related phenomena and applications thanks to the spin texture of their surface states. However, a versatile platform allowing for the exploitation of these assets is still lacking due to the difficult integration of these materials with the mainstream Si-based technology. Here, we exploit germanium as a substrate for the growth of Bi 2 Se 3 , a prototypical TI. We probe the spin properties of the Bi 2 Se 3 /Ge pristine interface by investigating the spin-to-charge conversion taking place in the interface states by means of a nonlocal detection method. The spin population is generated by optical orientation in Ge and diffuses toward the Bi 2 Se 3 , which acts as a spin detector. We compare the spin-to-charge conversion in Bi 2 Se 3 /Ge with the one taking place in Pt in the same experimental conditions. Notably, the sign of the spin-to-charge conversion given by the TI detector is reversed compared to the Pt one, while the efficiency is comparable. By exploiting first-principles calculations, we ascribe the sign reversal to the hybridization of the topological surface states of Bi 2 Se 3 with the Ge bands. These results pave the way for the implementation of highly efficient spin detection in TI-based architectures compatible with semiconductor-based platforms.

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Efficient charge-spin conversion and magnetization switching through the Rashba effect at topological-insulator/Ag interfaces

Cited by 58 publications

References 53 publications

Spin‐Orbit Torque Magnetization Switching in MoTe₂/Permalloy Heterostructures

Spin‐Orbit Torque Magnetization Switching in MoTe₂/Permalloy Heterostructures

Advances in Functional Nanomaterials Science

Spin orbitronics at a topological insulator-semiconductor interface

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Efficient charge-spin conversion and magnetization switching through the Rashba effect at topological-insulator/Ag interfaces

Cited by 58 publications

References 53 publications

Spin‐Orbit Torque Magnetization Switching in MoTe2/Permalloy Heterostructures

Spin‐Orbit Torque Magnetization Switching in MoTe2/Permalloy Heterostructures

Advances in Functional Nanomaterials Science

Spin orbitronics at a topological insulator-semiconductor interface

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Spin‐Orbit Torque Magnetization Switching in MoTe₂/Permalloy Heterostructures

Spin‐Orbit Torque Magnetization Switching in MoTe₂/Permalloy Heterostructures