Spin relaxation induced by interfacial effects in n-GaN/MgO/Co spin injectors

Liu, Xingchen; Tang, Ning; Fang, Chi; Wan, Caihua; Zhang, Shixiong; Zhang, Xiaoyue; Guan, Haijing; Zhang, Yunfan; Qian, Xuan; Ji, Yang; Ge, Weikun; Han, Xiufeng; Shen, Bo

doi:10.1039/d0ra00464b

Cited by 8 publications

(6 citation statements)

References 35 publications

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“…For structures with an in-plane magnetization, an increase of the electron spin polarization under an external magnetic field parallel to the electron spin was reported [25,28]. This phenomenon was named inverted Hanle effect, in contrast to the regular Hanle effect and attributed to the compensation of static random stray fields, produced near the FM layer due to the interface roughness.…”

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confidence: 99%

Recombination Time Mismatch and Spin Dependent Photocurrent at a Ferromagnetic-Metal–Semiconductor Tunnel Junction

et al. 2022

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We report on carrier dynamics in a spin photodiode based on a ferromagnetic-metal GaAs tunnel junction. We show that the helicity-dependent current is determined not only by the electron spin polarization and spin asymmetry of the tunneling, but in great part by a dynamical factor resulting from the competition between tunneling and recombination in the semiconductor, as well as by a specific quantity, the charge polarization of the photocurrent. The two latter factors can be efficiently controlled through an electrical bias. Under longitudinal magnetic field, we observe a strong increase of the signal arising from inverted Hanle effect, which is a fingerprint of its spin origin. Our approach represents a radical shift in the physical description of this family of emerging spin devices.

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mentioning

confidence: 99%

Recombination Time Mismatch and Spin Dependent Photocurrent at a Ferromagnetic-Metal–Semiconductor Tunnel Junction

et al. 2022

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“…It can be observed that the I-V characteristics of the GaN/Co Schottky junction exhibit a non-linear and symmetric behavior. Rowell criteria were applied to determine the tunneling process [18] . First, the conductance of the tunneling junctions should have a parabolic dependence on the applied voltage.…”

Section: Resultsmentioning

confidence: 99%

Spin injection into heavily-doped n-GaN via Schottky barrier

Sun,

Tang,

Chen

et al. 2023

J. Semicond.

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Spin injection and detection in bulk GaN were investigated by performing magnetotransport measurements at low temperatures. A non-local four-terminal lateral spin valve device was fabricated with Co/GaN Schottky contacts. The spin injection efficiency of 21% was achieved at 1.7 K. It was confirmed that the thin Schottky barrier formed between the heavily n-doped GaN and Co was conducive to the direct spin tunneling, by reducing the spin scattering relaxation through the interface states.

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“…The LSV device has two CFAS/n + -GaN contacts for spin injection and detection, and two Au/Ti ohmic contacts are formed at the ends of the n + -GaN layer. [24,28] The two-different shaped CFAS/GaN contacts (FM1 and FM2) were also connected to Au/Ti bonding pads to measure the spin transport through the n + -GaN layer. Before the spintransport measurements, we confirmed the current-voltage (I-V) characteristics of the CFAS/n + -GaN interfaces, as presented in Figure 5c, at 50-300 K. Here, the I-V characteristics of the CFAS/n + -GaN interface were evaluated by three-terminal methods, as illustrated in the inset.…”

Section: Spin Transport In Ganmentioning

confidence: 99%

“…Thus far, it has been demonstrated, even at room temperature, electrical spin injection into GaN in LED structures [20][21][22][23] and three-or four-terminal lateral device structures. [23][24][25][26][27][28][29] However, almost all of the previous related studies have used an insulating tunnel barrier such as MgO and AlN for electrical spin injection into GaN to solve the spin resistance mismatch problem, [30][31][32] resulting in high-resistance contacts with a resistance-area product (RA) higher than several MΩμm 2 . [20,21,29] If such high-resistance contacts were utilized, they would limit the future use of GaN in applications such as medical spin LEDs, [33] and spin-polarized lasers (spin lasers) for ultrafast switches, high-performance reconfigurable interconnects, and secure communications on chips.…”

Section: Introductionmentioning

confidence: 99%

Half‐Metallic Heusler Alloy/GaN Heterostructure for Semiconductor Spintronics Devices

Yamada

Kato

Ichikawa

et al. 2023

Adv Elect Materials

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Because spin-orbit coupling in wurtzite semiconductors is relatively weak compared with that in zincblende ones, the III-nitride semiconductor GaN is a promising material for high-performance optical semiconductor spintronic devices such as spin lasers. For the purpose of reducing the operating power of spin lasers, it is necessary to demonstrate highly efficient electrical spin injection from a ferromagnetic material into GaN with a low-resistance contact. Here, an epitaxial half-metallic Heusler alloy Co 2 FeAl x Si 1−x (CFAS)/GaN heterostructure is developed by inserting an ultrathin Co layer between the CFAS and GaN. The CFAS/n + -GaN heterojunctions clearly show tunnel conduction with very small rectification and a low resistance-area product of ≈3.8 k𝛀μm 2 , which is several orders of magnitude smaller than those reported in previous work, at room temperature. Nonlocal spin signals and a Hanle effect curve are observed at low temperatures using lateral spin-valve devices with the CFAS/n + -GaN contacts, suggesting pure spin current transport in bulk GaN. The spin transport is observed at temperatures as high as room temperature, with a high spin polarization of 0.2 at a low bias voltage less than 2.0 V. This study is expected to open a path to GaN-based spintronic devices with highly spin-polarized and low-resistance contacts.

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Spin relaxation induced by interfacial effects in n-GaN/MgO/Co spin injectors

Abstract: The interface-related spin relaxation in n-GaN/MgO/Co was investigated by both electrical Hanle effect and time resolved Kerr rotation spectrum.

Cited by 8 publications

References 35 publications

Recombination Time Mismatch and Spin Dependent Photocurrent at a Ferromagnetic-Metal–Semiconductor Tunnel Junction

Recombination Time Mismatch and Spin Dependent Photocurrent at a Ferromagnetic-Metal–Semiconductor Tunnel Junction

Spin injection into heavily-doped n-GaN via Schottky barrier

Half‐Metallic Heusler Alloy/GaN Heterostructure for Semiconductor Spintronics Devices

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