2D Materials最新文献

{"title":"Non-van der Waals MCrS2 nanosheets with tunable two-dimensional ferromagnetism","authors":"Na Luo, Hao Ma, Tao Zhang, Jiajing Wu, Zheng-Jie Chen, Minwei Xu, Yuanmiao Sun, Jing Peng","doi":"10.1088/2053-1583/ad70c6","DOIUrl":"https://doi.org/10.1088/2053-1583/ad70c6","url":null,"abstract":"Designing two-dimensional (2D) ferromagnetic materials with high Curie temperature is urgent for the development of spintronic technology. The exploration of non-van der Waals (vdW) ferromagnetic nanosheets play a vital role in enriching the 2D ferromagnetic materials family on account of the scarcity of vdW materials in nature. Herein, we report a non-vdW AgCrS₂ material with antiferro-to-ferro-magnetism transition when it thinned down to monolayer. Based on it, a universal ion-exchange strategy was employed to replace Ag⁺ by the M (M = Li⁺, Na⁺, K⁺) cations, acquiring a series of 2D non-vdW M<italic toggle=\"yes\">_x</italic>Ag_{0.5−<italic toggle=\"yes\">x</italic>}CrS₂ materials with tunable ferromagnetism. The Curie temperature is higher than the AgCrS₂ nanosheet, and reaches up to 160 K when M is K⁺. The theoretical calculations verify the ferromagnetism of AgCrS₂ and M<italic toggle=\"yes\">_x</italic>Ag_{0.5−<italic toggle=\"yes\">x</italic>}CrS₂ nanosheet originated from CrS₂ layer. The disorderly arranged M and Ag ions increase the asymmetry of the lattice structure of M<italic toggle=\"yes\">_x</italic>Ag_{0.5−<italic toggle=\"yes\">x</italic>}CrS₂, thereby strengthening the interlayer ferromagnetic coupling and raising the Curie temperature of the nanosheets. This work provides ideas for discovering more 2D ferromagnetic materials with high Curie temperature.","PeriodicalId":6812,"journal":{"name":"2D Materials","volume":"101 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Giant resistance switch in twisted transition metal dichalcogenide tunnel junctions","authors":"Marc Vila","doi":"10.1088/2053-1583/ad690f","DOIUrl":"https://doi.org/10.1088/2053-1583/ad690f","url":null,"abstract":"Resistance switching in multilayer structures are typically based on materials possessing ferroic orders. Here we predict an extremely large resistance switching based on the relative spin–orbit splitting in twisted transition metal dichalcogenide (TMD) monolayers tunnel junctions. Because of the valence band spin splitting which depends on the valley index in the Brillouin zone, the perpendicular electronic transport through the junction depends on the relative reciprocal space overlap of the spin-dependent Fermi surfaces of both layers, which can be tuned by twisting one layer. Our quantum transport calculations reveal a switching resistance larger than <inline-formula>\u0000<tex-math><?CDATA $10^6 %$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:msup><mml:mn>10</mml:mn><mml:mn>6</mml:mn></mml:msup><mml:mi mathvariant=\"normal\">%</mml:mi></mml:mrow></mml:math><inline-graphic xlink:href=\"tdmad690fieqn1.gif\"></inline-graphic></inline-formula> when the relative alignment of TMDs goes from 0^∘ to 60^∘ and when the angle is kept fixed at 60^∘ and the Fermi level is varied. By creating vacancies, we evaluate how inter-valley scattering affects the efficiency and find that the resistance switching remains large (<inline-formula>\u0000<tex-math><?CDATA $10^4 %$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:msup><mml:mn>10</mml:mn><mml:mn>4</mml:mn></mml:msup><mml:mi mathvariant=\"normal\">%</mml:mi></mml:mrow></mml:math><inline-graphic xlink:href=\"tdmad690fieqn2.gif\"></inline-graphic></inline-formula>) for typical values of vacancy concentration. Not only should this resistance switching be observed at room temperature due to the large spin splitting, but our results also show how twist angle engineering and control of van der Waals heterostructures could be used for next-generation memory and electronic applications.","PeriodicalId":6812,"journal":{"name":"2D Materials","volume":"51 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Liquid-phase exfoliated 2D materials for lithium-ion battery anode: current status and future direction","authors":"Ziyu Li, Xuefeng Liu, Ke Xu, Qiao Xie, Yage Li, Haijun Zhang, Shaowei Zhang, Wen Lei","doi":"10.1088/2053-1583/ad7271","DOIUrl":"https://doi.org/10.1088/2053-1583/ad7271","url":null,"abstract":"With the increasing need for energy and the swift advancement of the electric vehicle industry, the field of energy storage has garnered significant attention. Especially, lithium-ion batteries (LIBs) serve as crucial energy storage devices and have received particular attention. As an emerging class of electrode materials, two-dimensional (2D) materials have become promising candidates for solving the challenges of LIBs owing to their high theoretical capacity, high specific surface area, high ionic conductivity, and long cycle life. The research progress on 2D materials, especially those prepared through liquid-phase exfoliation (LPE), has shown great potential in improving the performance of LIBs. LPE is a powerful and efficient method for preparing 2D materials with various sizes and properties, which is suitable for practical applications. Given these, this paper underscores the great potential of 2D materials prepared via LPE as anode materials for LIBs. Meanwhile, the existence of challenges that need to be overcome in relation to the scalability of the LPE method and the use of 2D materials in practical applications are also proposed.","PeriodicalId":6812,"journal":{"name":"2D Materials","volume":"10 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dielectrophoretic direct assembling of Mxene flakes at the level of screen-printed interdigitated microelectrodes and their evaluation in gas sensing applications","authors":"Ina Turcan, Tudor Alexandru Filip, Tăchiță Vlad-Bubulac, Daniela Rusu, Marius Andrei Olariu","doi":"10.1088/2053-1583/ad6ba4","DOIUrl":"https://doi.org/10.1088/2053-1583/ad6ba4","url":null,"abstract":"Controlling, orientating, and assembling 2D materials is critical for their successful exploitation as active elements in various applications, particularly for sensors. Despite the increased interest in exploiting the properties of MXenes, to date, the direct dielectrophoretic assembly of this category of materials has not been reported. Thus, this work presents an experimental study on dielectrophoretic assembly of pristine MXene flakes at the level of screen-printed interdigitated microelectrodes. The development of MXene uniaxial ‘bridges’ across electrode micro-gaps can be controlled by convenient dielectrophoretic parameters such as voltage and frequency, which are thoroughly discussed. Moreover, appropriate frequencies for avoiding parasitic electrokinetic phenomena (AC electro-osmosis, electrothermal effect) that hamper the application of dielectrophoresis were identified. Finally, the proposed methodology for assembling MXene flakes demonstrates its feasibility of being used for development of chemiresistors as of satisfactory response of pristine MXene ‘bridges’ to ethanol atmosphere.","PeriodicalId":6812,"journal":{"name":"2D Materials","volume":"13 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Raman spectroscopy of atomically thin HfX2 (X=S, Se)","authors":"Chhor Yi Ly, Chenda Vong, Tharith Sriv, Hyeonsik Cheong","doi":"10.1088/2053-1583/ad70c8","DOIUrl":"https://doi.org/10.1088/2053-1583/ad70c8","url":null,"abstract":"We investigated interlayer modes of few-layer HfX₂ (X = S, Se) by using low-frequency micro-Raman spectroscopy with three excitation energies (1.96 eV, 2.33 eV, 2.54 eV) under vacuum condition (∼10⁻⁶Torr). We observed interlayer modes in HfSe₂ when the 2.54 eV excitation energy was used. The low-frequency Raman spectra reveal a series of shear and breathing modes (&lt;50 cm⁻¹) that are helpful for identifying the number of layers. The in-plane <italic toggle=\"yes\">E</italic>_g and out-of-plane <italic toggle=\"yes\">A</italic>_1g modes of HfSe₂ are located at ∼150 cm⁻¹ and ∼200 cm⁻¹, respectively. In HfS₂, in-plane <italic toggle=\"yes\">E</italic>_g and out-of-plane <italic toggle=\"yes\">A</italic>_1g optical phonons are observed at ∼260 cm⁻¹ and ∼337 cm^−1, respectively. The in-plane and out-of-plane force constants of atomically thin HfSe₂ are obtained to be 1.87 × 10¹⁹N m⁻³ and 6.55 × 10¹⁹N m⁻³, respectively, by fitting the observed interlayer modes using the linear chain model. These results provide valuable information on materials parameters for device designs using atomically-thin layered HfX₂ (X = S, Se).","PeriodicalId":6812,"journal":{"name":"2D Materials","volume":"45 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconfigurable dielectric engineered WSe2/HZO mem-transistor","authors":"Tong Tong, Yongli He, Yuan Gao, Yukang Liu, Kan Liao, Weisheng Li","doi":"10.1088/2053-1583/ad70c9","DOIUrl":"https://doi.org/10.1088/2053-1583/ad70c9","url":null,"abstract":"Hybrid systems coupling two-dimensional (2D) semiconductors with functional ferroelectrics are attracting increasing attention owing to their excellent electronic/optoelectronic properties and new functionalities through the multiple heterointerface interactions. In our device architecture, interfacial states are introduced on the ferroelectric Hf_0.5Zr_0.5O₂ thin film as a gate dielectric layer for the charge trapping effect. Utilizing the collaborative effects of charge trapping and ferroelectric polarization behavior, a multifunctional 2D WSe₂/HZO memtransistor is demonstrated with an ultra-low off-state (dark) current of 10⁻¹³ A, high on/off ratio of 10⁶ and linear conductance update. This device exhibits reliable memory properties and tunable synaptic functions including short-term plasticity/long-term plasticity, paired pulse facilitation, spike-timing dependent plasticity, synaptic potentiation/depression, and filtering in a single device. Extensive endurance tests ensure robust stability (1000 switching cycles, 2000 s holding time) and the synaptic weight update in the device exhibits excellent linearity. Based on the experimental data, our devices eventually achieve an accuracy of 94.8% in artificial neural network simulations. These results highlight a new approach for constructing hybrid systems coupling 2D semiconductors with functional ferroelectrics in a single device to tune synaptic weight, optimize circuit design, and build artificial neuromorphic computing systems.","PeriodicalId":6812,"journal":{"name":"2D Materials","volume":"294 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetoresistance in two-dimensional materials and van der Waals heterostructures","authors":"Na Xin","doi":"10.1088/2053-1583/ad70c7","DOIUrl":"https://doi.org/10.1088/2053-1583/ad70c7","url":null,"abstract":"Magnetoresistance (MR) refers to the alteration in electrical resistance within a material when influenced by a magnetic field. Studying MR at the atomic level holds a significant interest both in fundamental research and practical applications. Atomically thin two-dimensional (2D) van der Waals materials and their heterostructures offer an unprecedented platform to investigate MR, thanks to the very broad range of properties and no requirement for lattice matching. Here, we review the various mechanisms of MR effect in 2D materials and their heterostructures, including tunneling MR, extremely large unsaturated MR, layer MR, and colossal MR, as well as explore their potential in device applications. Furthermore, we discuss the limitations and main challenges that still exist for the development of practical devices based on MR and provide our considerations towards real applications.","PeriodicalId":6812,"journal":{"name":"2D Materials","volume":"74 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anisotropic effects in two-dimensional materials","authors":"Alexander N Rudenko, Mikhail I Katsnelson","doi":"10.1088/2053-1583/ad64e1","DOIUrl":"https://doi.org/10.1088/2053-1583/ad64e1","url":null,"abstract":"Among a huge variety of known two-dimensional (2D) materials, some of them have anisotropic crystal structures; examples include different systems such as a few-layer black phosphorus (phosphorene), beryllium nitride BeN₄, the van der Waals magnet CrSBr, and rhenium dichalcogenides ReX₂. As a consequence, their optical and electronic properties are highly anisotropic as well. In some cases, the anisotropy results in not only smooth renormalization of observable properties in comparison with the isotropic case, but in the appearance of dramatically new physics. The examples are hyperbolic plasmons and excitons, strongly anisotropic ordering of adatoms at the surface of 2D or van der Waals materials, and essential changes in transport and superconducting properties. Here, we present a systematic review of the electronic structure, transport, and optical properties of several representative groups of anisotropic 2D materials, including semiconductors, anisotropic Dirac and semi-Dirac materials, and superconductors.","PeriodicalId":6812,"journal":{"name":"2D Materials","volume":"43 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical control of berry curvature in gated WSe2 bilayers","authors":"Majeed Ur Rehman, Zia Ur Rahman, Azizur Rahman, Waqas Ahmad, Sadeeq Ullah","doi":"10.1088/2053-1583/ad6ba2","DOIUrl":"https://doi.org/10.1088/2053-1583/ad6ba2","url":null,"abstract":"Unlike single layers of 2H transition metal dichalcogenides (TMDCs), bilayers of 2H TMDCs maintain inversion and time reversal (TR) symmetries, resulting in a vanishing Berry curvature (<inline-formula>\u0000<tex-math><?CDATA $Omega(k)sim0)$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:mi mathvariant=\"normal\">Ω</mml:mi><mml:mo stretchy=\"false\">(</mml:mo><mml:mi>k</mml:mi><mml:mo stretchy=\"false\">)</mml:mo><mml:mo>∼</mml:mo><mml:mn>0</mml:mn><mml:mo stretchy=\"false\">)</mml:mo></mml:mrow></mml:math><inline-graphic xlink:href=\"tdmad6ba2ieqn1.gif\"></inline-graphic></inline-formula> that inhibits various potential transport phenomena. A nonzero Berry curvature <inline-formula>\u0000<tex-math><?CDATA $(Omega(k)neq0)$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:mo stretchy=\"false\">(</mml:mo><mml:mi mathvariant=\"normal\">Ω</mml:mi><mml:mo stretchy=\"false\">(</mml:mo><mml:mi>k</mml:mi><mml:mo stretchy=\"false\">)</mml:mo><mml:mo>≠</mml:mo><mml:mn>0</mml:mn><mml:mo stretchy=\"false\">)</mml:mo></mml:mrow></mml:math><inline-graphic xlink:href=\"tdmad6ba2ieqn2.gif\"></inline-graphic></inline-formula> is imperative for the occurrence of several unconventional transport phenomena, including the anomalous Hall effect and the anomalous Nernst effect. To overcome this limitation, we break these symmetries in bilayer TMDCs using electrostatic gating and circularly polarized light as external means. For non-gated WSe₂ bilayers, circularly polarized light breaks TR symmetry, creating a finite Berry curvature signal in both conduction and valence bands, controllable by light intensity and its polarity. In gated WSe₂ bilayers, where inversion symmetry is also broken, we observe a sign reversal in Berry curvature within the conduction bands, the extent of which depends on the relative strengths of the electric gating and light intensity. Overall, under finite bias and light intensity, the 2H bilayers of WSe₂ exhibits finite spin Hall, valley Hall, and anomalous Hall conductivities, which depend on the strengths of the applied perturbations.","PeriodicalId":6812,"journal":{"name":"2D Materials","volume":"134 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The importance of interlaboratory studies for robust measurements of graphene and other 2D materials","authors":"Keith R Paton, Andrew J Pollard","doi":"10.1088/2053-1583/ad6911","DOIUrl":"https://doi.org/10.1088/2053-1583/ad6911","url":null,"abstract":"This perspective article presents the current state of interlaboratory studies in graphene and other 2D materials. These interlaboratory studies are mostly coordinated via the Versailles Project on Advanced Materials and Standards and are crucial in establishing robust and validated protocols for measuring key properties of these materials. These protocols can then be included in international documentary standards. We summarise the key findings of completed studies and outline the approach of those that are currently underway. An outline of future needs is also presented, highlighting gaps in the current scope of activities and therefore where the focus of future studies should be.","PeriodicalId":6812,"journal":{"name":"2D Materials","volume":"14 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}