npj 2D Materials and Applications最新文献_第8页

Tunable magnetic confinement effect in a magnetic superlattice of graphene 石墨烯磁性超晶格中的可调磁约束效应

IF 9.7 2区材料科学

npj 2D Materials and Applications Pub Date : 2024-04-11 DOI: 10.1038/s41699-024-00468-7

Onur Tosun, Preetha Sarkar, Chang Qian, Matthew Gilbert, Qian Chen, Nadya Mason

{"title":"Tunable magnetic confinement effect in a magnetic superlattice of graphene","authors":"Onur Tosun, Preetha Sarkar, Chang Qian, Matthew Gilbert, Qian Chen, Nadya Mason","doi":"10.1038/s41699-024-00468-7","DOIUrl":"10.1038/s41699-024-00468-7","url":null,"abstract":"Two-dimensional van der Waals materials such as graphene present an opportunity for band structure engineering using custom superlattice potentials. In this study, we demonstrate how self-assemblies of magnetic iron-oxide (Fe3O4) nanospheres stacked on monolayer graphene generate a proximity-induced magnetic superlattice in graphene and modify its band structure. Interactions between the nanospheres and the graphene layer generate superlattice Dirac points in addition to a gapped energy spectrum near the K and K′ valleys, resulting in magnetic confinement of quasiparticles around the nanospheres. This is evidenced by gate-dependent resistance oscillations, observed in our low temperature transport measurements, and confirmed by self-consistent tight binding calculations. Furthermore, we show that an external magnetic field can tune the magnetic superlattice potential created by the nanospheres, and thus the transport characteristics of the system. This technique for magnetic-field-tuned band structure engineering using magnetic nanostructures can be extended to a broader class of 2D van der Waals and topological materials.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-9"},"PeriodicalIF":9.7,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00468-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140544581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Exploration of the two-dimensional transition metal phosphide MoP2 as anode for Na/K ion batteries 二维过渡金属磷化物 MoP2 作为 Na/K 离子电池阳极的探索

IF 9.7 2区材料科学

npj 2D Materials and Applications Pub Date : 2024-04-06 DOI: 10.1038/s41699-024-00453-0

Junjie Jin, Udo Schwingenschlögl

引用次数: 0

Spin-reorientation driven emergent phases and unconventional magnetotransport in quasi-2D vdW ferromagnet Fe4GeTe2 准二维 vdW 铁磁体 Fe4GeTe2 中的自旋定向驱动新兴相和非常规磁传输

IF 9.7 2区材料科学

npj 2D Materials and Applications Pub Date : 2024-04-05 DOI: 10.1038/s41699-024-00463-y

Riju Pal, Buddhadeb Pal, Suchanda Mondal, Rajesh O. Sharma, Tanmoy Das, Prabhat Mandal, Atindra Nath Pal

{"title":"Spin-reorientation driven emergent phases and unconventional magnetotransport in quasi-2D vdW ferromagnet Fe4GeTe2","authors":"Riju Pal, Buddhadeb Pal, Suchanda Mondal, Rajesh O. Sharma, Tanmoy Das, Prabhat Mandal, Atindra Nath Pal","doi":"10.1038/s41699-024-00463-y","DOIUrl":"10.1038/s41699-024-00463-y","url":null,"abstract":"Non-trivial spin textures driven by strong exchange interaction, magneto-crystalline anisotropy, and electron correlation in a low-dimensional magnetic material often lead to unusual electronic transitions. Through a combination of transport experiments in exfoliated nanoflakes down to 16 layers and first principle calculations, we unravel emergent electronic phases in quasi-2D van der Waals ferromagnet, Fe4GeTe2, possessing ferromagnetic TC ~ 270 K, along with a spin-reorientation transition (TSR ~ 120 K) with the change of magnetic easy axis. Two electronic transitions are identified. The first transition near TSR exhibits a sharp fall in resistivity, followed by a sign change in the ordinary Hall coefficient (R0), together with, maximum negative magnetoresistance (MR) and anomalous Hall conductivity. Another unusual electronic transition, hitherto unknown, is observed near ~ 40–50 K (TQ), where R0 again changes sign and below which, the resistivity shows a quadratic temperature dependence, and MR becomes positive. An analysis of the experimental data further uncovers the role of competing inelastic scattering processes in anomalous magnetotransport behavior. The density-functional theory based first-principle calculations unveil two possible magnetic phases, followed by a low-energy model Hamiltonian which captures the essence of these phases as well as explains the observed magnetotransport behavior. Thus, we demonstrate an interplay between magnetism and band topology and its consequence on electron transport in Fe4GeTe2, important for spintronic applications.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-11"},"PeriodicalIF":9.7,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00463-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140348884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Logic-in-memory application of ferroelectric-based WS2-channel field-effect transistors for improved area and energy efficiency 基于铁电的 WS2 沟道场效应晶体管的逻辑内存应用，提高面积和能效

IF 9.7 2区材料科学

npj 2D Materials and Applications Pub Date : 2024-04-01 DOI: 10.1038/s41699-024-00466-9

Huijun Kim, Juhwan Park, Hanggyo Jung, Changho Ra, Jongwook Jeon

{"title":"Logic-in-memory application of ferroelectric-based WS2-channel field-effect transistors for improved area and energy efficiency","authors":"Huijun Kim, Juhwan Park, Hanggyo Jung, Changho Ra, Jongwook Jeon","doi":"10.1038/s41699-024-00466-9","DOIUrl":"10.1038/s41699-024-00466-9","url":null,"abstract":"In this study, we applied ferroelectrics to the gate stack of Field Effect Transistors (FETs) with a 2D transition-metal dichalcogenide (TMDC) channel, actively researching for sub-2nm technology node implementation. Subsequently, we analyzed the circuit characteristics of Logic-in-Memory (LiM) operation and utilized LiM features after applying ferroelectrics to achieve a single-device configuration. Based on well-calibrated simulations, we performed compact modeling in a circuit simulator to depict the temperature-dependent electrical characteristics of ferroelectric FETs with a double gate structure and 2D channel (DG 2D-FeFET) in sub-2nm dimensions. Through this, we have confirmed that the 2D FeFET-based LiM technology, designed for the 2 nm technology node, exhibits superior characteristics in terms of delay, power/energy consumption, and circuit area under all temperature conditions, compared to the conventional CMOS technology based on 2D FETs. This verification serves as proof of the future technological potential of 2D-FeFET in extremely scaled-down technology nodes.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-9"},"PeriodicalIF":9.7,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00466-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140333375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hometronics – accessible production of graphene suspensions for health sensing applications using only household items 家居电子学--仅使用家居用品就可生产用于健康传感应用的石墨烯悬浮物

IF 9.7 2区材料科学

npj 2D Materials and Applications Pub Date : 2024-03-30 DOI: 10.1038/s41699-024-00467-8

Adel K. A. Aljarid, Jasper Winder, Cencen Wei, Arvind Venkatraman, Oliver Tomes, Aaron Soul, Dimitrios G. Papageorgiou, Matthias E. Möbius, Conor S. Boland

引用次数: 0

Atomistic description of conductive bridge formation in two-dimensional material based memristor 基于二维材料的忆阻器中导电桥形成的原子论描述

IF 9.7 2区材料科学

npj 2D Materials and Applications Pub Date : 2024-03-27 DOI: 10.1038/s41699-024-00465-w

Sanchali Mitra, Santanu Mahapatra

{"title":"Atomistic description of conductive bridge formation in two-dimensional material based memristor","authors":"Sanchali Mitra, Santanu Mahapatra","doi":"10.1038/s41699-024-00465-w","DOIUrl":"10.1038/s41699-024-00465-w","url":null,"abstract":"In-memory computing technology built on 2D material-based nonvolatile resistive switches (aka memristors) has made great progress in recent years. It has however been debated whether such remarkable resistive switching is an inherent property of the 2D materials or if the metal electrode plays any role? Can the metal atoms penetrate through the crystalline 2D materials to form conductive filaments as observed in amorphous oxide-based memristors? To find answers, here we investigate MoS2 and h-BN-based devices with electrochemically passive and active (metal) electrodes using reactive molecular dynamics with a charge equilibration approach. We find that the SET and RESET processes in active electrode-based multilayer devices involve the formation and disruption of metal filaments linking the two electrodes exclusively through the grain boundaries, the configuration of which affects the volatility of the resistive switching. Whereas the switching mechanisms in passive electrode-based devices require the formation of interlayer B-N bonds and popping of the S atom to the Mo plane at the point defects. We also show that metal atom adsorption at the point defects causes resistive switching in monolayer MoS2. Our atomic-level understanding provides explanations to the apparently contradictory experimental findings and enables defect-engineering guidelines in 2D materials for such disruptive technology.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-14"},"PeriodicalIF":9.7,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00465-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140310417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Graphene oxide-based membranes for water desalination and purification 基于氧化石墨烯的脱盐和净水膜

IF 9.7 2区材料科学

npj 2D Materials and Applications Pub Date : 2024-03-27 DOI: 10.1038/s41699-024-00462-z

Saurabh Kr Tiwary, Maninderjeet Singh, Shubham Vasant Chavan, Alamgir Karim

{"title":"Graphene oxide-based membranes for water desalination and purification","authors":"Saurabh Kr Tiwary, Maninderjeet Singh, Shubham Vasant Chavan, Alamgir Karim","doi":"10.1038/s41699-024-00462-z","DOIUrl":"10.1038/s41699-024-00462-z","url":null,"abstract":"Millions of people across the globe are severely afflicted because of water potability issues, and to proffer a solution to this crisis, efficient and cost-effective desalination techniques are necessitated. Membranes, in particular Graphene-derived membranes, have emerged as a potential answer to this grave problem because of their tunable ionic and molecular sieving capability, thin structure, and customizable microstructure. Among graphene-derived membranes, Graphene Oxide membranes have been the most promising, given the replete presence of oxygen-containing functional groups on its surface. However, the prospects of commercial applicability of these membranes are currently plagued by uneven stacking, crossflow delamination, flawed pores, screening and pH effects, and horizontal defects in the membrane. In addition, due to the selectivity–permeability trade-off that commonly exists in all membranes, the separation efficiency is negatively influenced. This review, while studying these challenges, aims to outline the most recent ground-breaking developments in graphene-based membrane technology, encompassing their separation mechanism, selectivity, adjustable mechanical characteristics, and uses. Additionally, we have covered in detail how several process variables such as temperature, total oxygen concentration, and functional groups affect the effectiveness of membrane separation with the focal point tilted toward studying the currently used intercalation techniques and effective nanomaterial graphene oxide membranes for water desalination","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-19"},"PeriodicalIF":9.7,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00462-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140310394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Enhancing dielectric passivation on monolayer WS2 via a sacrificial graphene oxide seeding layer 通过牺牲氧化石墨烯播种层增强单层 WS2 的介电钝化

IF 9.7 2区材料科学

npj 2D Materials and Applications Pub Date : 2024-03-27 DOI: 10.1038/s41699-024-00464-x

P.-J. Wyndaele, J.-F. de Marneffe, S. Sergeant, C. J. L. de la Rosa, S. Brems, A. M. Caro, S. De Gendt

{"title":"Enhancing dielectric passivation on monolayer WS2 via a sacrificial graphene oxide seeding layer","authors":"P.-J. Wyndaele, J.-F. de Marneffe, S. Sergeant, C. J. L. de la Rosa, S. Brems, A. M. Caro, S. De Gendt","doi":"10.1038/s41699-024-00464-x","DOIUrl":"10.1038/s41699-024-00464-x","url":null,"abstract":"The full utilization of two-dimensional transition metal dichalcogenides (2D TMDCs) faces several challenges, among which is realizing uniform material deposition on the 2D surface. Typical strategies to enable material growth lead to a poor interface quality, degrading the 2D TMDC’s properties. In this work, a sacrificial, graphene oxide-based seeding layer is used (1) as passivation layer, protecting the underlying 2D TMDC and (2) as nucleation layer, enabling uniform material growth. Graphene is transferred on monolayer WS2, establishing a high-quality van der Waals interface. After transfer, the polymeric residues on graphene are cleaned via a combination of wet- and dry treatments and functionalized via dry UV/O3 oxidation. The rate of graphene oxidation is shown to be substrate dependent, which is explained by UV light-induced ultrafast charge transfer between the graphene and WS2 monolayer. The carbon-oxygen functionalities serve as nucleation sites in a subsequent HfO2 ALD process, achieving more uniform dielectric growth and faster layer closure compared to direct deposition. The graphene-based nucleation- / passivation approach offers adaptability, allowing for tailored surface chemistry to enable any alternative material growth, while maintaining a prefect van der Waals interface.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-11"},"PeriodicalIF":9.7,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00464-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140310408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Inducing room-temperature valley polarization of excitonic emission in transition metal dichalcogenide monolayers 诱导过渡金属二卤化物单层中激子发射的室温谷极化

IF 9.7 2区材料科学

npj 2D Materials and Applications Pub Date : 2024-03-20 DOI: 10.1038/s41699-024-00459-8

Sergii Morozov, Torgom Yezekyan, Christian Wolff, Sergey I. Bozhevolnyi, N. Asger Mortensen

{"title":"Inducing room-temperature valley polarization of excitonic emission in transition metal dichalcogenide monolayers","authors":"Sergii Morozov, Torgom Yezekyan, Christian Wolff, Sergey I. Bozhevolnyi, N. Asger Mortensen","doi":"10.1038/s41699-024-00459-8","DOIUrl":"10.1038/s41699-024-00459-8","url":null,"abstract":"The lowest energy states in transition metal dichalcogenide (TMD) monolayers follow valley selection rules, which have attracted vast interest due to the possibility of encoding and processing of quantum information. However, these quantum states are strongly affected by temperature-dependent intervalley scattering leading to complete valley depolarization, which hampers practical applications at room temperature. Therefore, for achieving clear and robust valley polarization in TMD monolayers one needs to suppress parasitic depolarization processes, which is the central challenge in the growing field of valleytronics. Here, in electron-doping experiments on TMD monolayers, we show that strong doping levels beyond 1013 cm−2 can induce 61% and 37% valley contrast at room temperature in tungsten diselenide and molybdenum diselenide monolayers, respectively. Our findings demonstrate that charged excitons in TMD monolayers hold the potential for the development of efficient valleytronic devices functional at 300 K.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-6"},"PeriodicalIF":9.7,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00459-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140181739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Variability and high temperature reliability of graphene field-effect transistors with thin epitaxial CaF2 insulators 具有薄外延 CaF2 绝缘层的石墨烯场效应晶体管的变异性和高温可靠性

IF 9.7 2区材料科学

npj 2D Materials and Applications Pub Date : 2024-03-19 DOI: 10.1038/s41699-024-00461-0

Yu. Yu. Illarionov, T. Knobloch, B. Uzlu, A. G. Banshchikov, I. A. Ivanov, V. Sverdlov, M. Otto, S. L. Stoll, M. I. Vexler, M. Waltl, Z. Wang, B. Manna, D. Neumaier, M. C. Lemme, N. S. Sokolov, T. Grasser

{"title":"Variability and high temperature reliability of graphene field-effect transistors with thin epitaxial CaF2 insulators","authors":"Yu. Yu. Illarionov, T. Knobloch, B. Uzlu, A. G. Banshchikov, I. A. Ivanov, V. Sverdlov, M. Otto, S. L. Stoll, M. I. Vexler, M. Waltl, Z. Wang, B. Manna, D. Neumaier, M. C. Lemme, N. S. Sokolov, T. Grasser","doi":"10.1038/s41699-024-00461-0","DOIUrl":"10.1038/s41699-024-00461-0","url":null,"abstract":"Graphene is a promising material for applications as a channel in graphene field-effect transistors (GFETs) which may be used as a building block for optoelectronics, high-frequency devices and sensors. However, these devices require gate insulators which ideally should form atomically flat interfaces with graphene and at the same time contain small densities of traps to maintain high device stability. Previously used amorphous oxides, such as SiO2 and Al2O3, however, typically suffer from oxide dangling bonds at the interface, high surface roughness and numerous border oxide traps. In order to address these challenges, here we use 2 nm thick epitaxial CaF2 as a gate insulator in GFETs. By analyzing device-to-device variability for about 200 devices fabricated in two batches, we find that tens of them show similar gate transfer characteristics. Our statistical analysis of the hysteresis up to 175oC has revealed that while an ambient-sensitive counterclockwise hysteresis can be present in some devices, the dominant mechanism is thermally activated charge trapping by border defects in CaF2 which results in the conventional clockwise hysteresis. We demonstrate that both the hysteresis and bias-temperature instabilities in our GFETs with CaF2 are comparable to similar devices with SiO2 and Al2O3. In particular, we achieve a small hysteresis below 0.01 V for equivalent oxide thickness (EOT) of about 1 nm at the electric fields up to 15 MV cm−1 and sweep times in the kilosecond range. Thus, our results demonstrate that crystalline CaF2 is a promising insulator for highly-stable GFETs.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-10"},"PeriodicalIF":9.7,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00461-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140181737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0