Large edge magnetism in oxidized few-layer black phosphorus nanomeshes

Nakanishi, Y.; Ishi, Ayumi; Ohata, C.; Soriano, David; Iwaki, Ryo; Nomura, K.; Hasegawa, Miki; Nakamura, Tsuneyoshi; Katsumoto, Shingo; Roche, Stephan; Haruyama, J.

doi:10.1007/s12274-016-1355-8

Cited by 31 publications

(23 citation statements)

References 38 publications

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“…The absence of any substantial background magnetic impurities and magnetic contamination (e.g., Ni, Fe, Co) has been carefully confirmed following the previous methods reported in Ref. 16; i.e., (1) the XPS measurements, (2) Confirmation of no magnetic hysteresis loops in few-layer bulk flakes produced using the same fabrication processes as for NM without pore formation, and that in which Ar gas etching process was carried out without using a porous alumina template mask as in the case of NM. (3) Significant differences between magnetization curves for H-and O-hBNNMs discard the introduction of magnetic impurities introduced during the fabrication process.…”

supporting

confidence: 70%

“…We discuss correlation of the observed dependence of the magnetism on annealing temperatures with the formation of the zigzag pore edges, based on our previous results, which revealed T c of 700 C and 300 C in GNMs and BPNMs, respectively, at which magnetization exhibited the largest FM values. These FM values were attributed to the formation of the zigzag-atomic type pore edges, which were confirmed by Raman spectrum and magnetic force microscope, 5,6,16 by the T c annealing through the edge atomic reconstruction. There are some theories and calculations for the formation of zigzag edges.…”

mentioning

confidence: 56%

“…[12][13][14][15][16]21 We clarified that O-terminated zigzag pore edges in few-layer BPNMs produce evident FM with magnitude $100 times/area larger than that reported for the H-GNMs at room temperature. 16 These behaviors highly contrasted with those of H-GNMs as mentioned above. The edge FM was attributed to ferromagnetic spin coupling of the edge P¼O bonds and the interlayer ferromagnetic spin coupling due to AB stacking.…”

mentioning

confidence: 68%

“…(4) The careful fabrication process (i.e., bulk hBNs mechanically exfoliated by non-magnetic scotch tapes, porous alumina templates fabricated using extremely pure Al substrate (99.99%) for anodic oxidation, the etching process of hBNs for pore formation using Ar gas, and use of only plastic tweezers during all the fabrication processes). Figure 2(a) shows a typical measurement result of the magnetization of the few-layer O-hBNNM annealed at 500 C. Ferromagnetic (FMC)-hysteresis loops are clearly observed within order $10 À4 emu, which is almost similar to the magnitude of FM of the few-layer O-BPNMs 16 and larger than that of the H-GNMs. 5,6 This suggests that spin alignment of the edge O atom is strongly associated with the observed FM.…”

mentioning

confidence: 90%

“…1(b)). Following the non-lithographic method used to engineer GNMs and BPNMs (i.e., using nanoporous alumina template as an etching mask [5][6][7][8][9]16 ), few-layer hBNNM have been fabricated and field-emission SEM (FESEM) ( Fig. 1(c)) and atomic-force microscope (Figs.…”

mentioning

confidence: 99%

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Hexagonal boron-nitride nanomesh magnets

Ohata

Tagami

Nakanishi

et al. 2016

Applied Physics Letters

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The formation of magnetic and spintronic devices using two-dimensional (2D) atom-thin layers has attracted attention. Ferromagnetisms (FMs) arising from zigzag-type atomic structure of edges of 2D atom-thin materials have been experimentally observed in graphene nanoribbons, hydrogen (H)-terminated graphene nanomeshes (NMs), and few-layer oxygen (O)-terminated black phosphorus NMs. Herein, we report room-temperature edge FM in few-layer hexagonal boron-nitride (hBN) NMs. O-terminated hBNNMs annealed at 500 C show the largest FM, while it completely disappears in H-terminated hBNNMs. When hBNNMs are annealed at other temperatures, amplitude of the FM significantly decreases. These are highly in contrast to the case of graphene NMs but similar to the cases of black phosphorus NM and suggest that the hybridization of the O atoms with B(N) dangling bonds of zigzag pore edges, formed at the 500 C annealing, strongly contribute to this edge FM. Room-temperature FM realizable only by exposing hBNNMs into air opens the way for high-efficiency 2D flexible magnetic and spintronic devices without the use of rare magnetic elements.

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confidence: 70%

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confidence: 56%

mentioning

confidence: 68%

mentioning

confidence: 90%

mentioning

confidence: 99%

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Hexagonal boron-nitride nanomesh magnets

Ohata

Tagami

Nakanishi

et al. 2016

Applied Physics Letters

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Applications of Phosphorene and Black Phosphorus in Energy Conversion and Storage Devices

Pang

Bachmatiuk

Yin

et al. 2017

Advanced Energy Materials

448

253

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Black phosphorus was first synthesized by Bridgman in 1914 [1] but has been less intensively studied in the past century due The successful isolation of phosphorene (atomic layer thick black phosphorus) in 2014 has currently aroused the interest of 2D material researchers. In this review, first, the fundamentals of phosphorus allotropes, phosphorene, and black phosphorus, are briefly introduced, along with their structures, properties, and synthesis methods. Second, the readers are presented with an overview of their energy applications. Particularly in electrochemical energy storage, the large interlayer spacing (0.53 nm) in phosphorene allows the intercalation/deintercalation of larger ions as compared to its graphene counterpart. Therefore, phosphorene may possess greater potential for high electrochemical performance. In addition, the status of lithium ion batteries as well as secondary sodium ion batteries is reviewed. Next, each application for energy generation, conversion, and storage is described in detail with milestones as well as the challenges. These emerging applications include supercapacitors, photovoltaic devices, water splitting, photocatalytic hydrogenation, oxygen evolution, and thermoelectric generators. Finally the fast-growing dynamic field of phosphorene research is summarized and perspectives on future possibilities are presented calling on the efforts of chemists, physicists, and material scientists

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Ambient Degradation‐Induced Spin Paramagnetism in Phosphorene

Chen

Zhou

Pan

et al. 2018

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as spin diode, spin transistor, and spintronics devices and so on) [15][16][17] and thus would significantly widen the application scope. Nevertheless, the potential in spintronics device applications is limited by BP's intrinsic nonmagnetism. [18] Thus, inducing a magnetic response in BP is a critical step. So far there have been many theoretical studies predicting that defects in BP such as point vacancy, zigzag (ZZ) edge, or doping heteroatoms would create local spins and they can in principle couple (anti)ferromagnetically. [18][19][20][21][22] For instance, each ZZ edge [18,19] or point vacancy [21] can theoretically generate 1 µ B magnetic moment in BP. However, the experimental evidence for such edge-/ defect-induced magnetism is still lacking.It has been widely reported that BP may undergo a fast degradation in hours under ambient conditions, [23][24][25][26][27] and the degradation can largely change its semiconducting properties. [28][29][30] Nevertheless, few would have suspected or predicted whether ambient degradation of BP would harbor magnetism. In fact, during the ambient degradation, the edges or vacancies are less stable and more easily bonded with O adatoms than the pristine surface of BP sheet; [24,31] as a result, the edge O adatoms at both edges and vacancies may play an important role in the generation of magnetism.Here, we report that ambient degradation of BP can create the notable paramagnetism with magnetization limited to 0.975 emu g −1 . Such magnetism is inherent, and any degree of degradation leads to notable paramagnetism. Its Landau factor g measured by electron spin resonance (ESR) spectrum is ≈1.995, indicating that the magnetization contributes by spin rather than orbital moments. Details investigations show that such magnetism most likely results from the unsaturated phosphorus in the vacancies which can be stabilized by O adatoms. We show that the magnetism of BP can be tuned by changing any one of the ambient factors (ambient temperature, humidity, and light intensity), and can be stabilized by exposing BP in argon.Few-layer BP was prepared by liquid exfoliation of bulk BP (Figure S1, Supporting Information). [32] Bulk BP is of 20 µm lateral size ( Figure S1a, Supporting Information), has a high crystallinity ( Figure S1b, Supporting Information), and a low oxidization percent of 2.15% ( Figure S1c, Supporting Information), and is nonmagnetic ( Figure S1d, Supporting Information). To investigate the ambient degradation of BP, weThe sizeable direct bandgap, high mobility, and long spin lifetimes at room temperature offer black phosphorus (BP) potential applications in spin-based semiconductor devices. Toward these applications, a critical step is creating a magnetic response in BP, which is arousing much interest. It is reported here that ambient degradation of BP, which is immediate and inevitable and greatly changes the semiconducting properties, creates magnetic moments, and any degree of degradation leads to notable paramagnetism. Its Landau factor g measured is ≈1.995, r...

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Large edge magnetism in oxidized few-layer black phosphorus nanomeshes

Cited by 31 publications

References 38 publications

Hexagonal boron-nitride nanomesh magnets

Hexagonal boron-nitride nanomesh magnets

Applications of Phosphorene and Black Phosphorus in Energy Conversion and Storage Devices

Ambient Degradation‐Induced Spin Paramagnetism in Phosphorene

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