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Nano Research 2019年第11期12卷 2788-2795页

作者： Yansheng Liu Feng Luo imdea nanoscience Faraday 9Ciudad Unriversitaria de CantoblancoMadrid 28049Spain

In this paper,the study of using masks to directly generate large area,highly ordered and periodical nanostructure has been *** Au nano-discs(NDs)arrays have been fabricated on top of graphene by using holey SigN4 mask which is directly fixed on top of graphene and Au metal is deposited through the holes in mask by thermal evaporation method under vacuum *** fabrication method provides an easy,fast and cost efficiency way to generate periodical ***,Au nanoholes(NHs)structure has been studied by using holey SigN4 as a *** surface-enhanced Raman scattering(SERS)sensitvities of periodical Au NDs/graphene and graphene/Au NHs hybrid structures have been systematically *** internal mechanisms could be explained by chemical mechanism effect of graphene and electromagnetic mechanism effect of metallic *** enhancement factors have been systematically investigated by varying the diameter and the thickness of Au discs and Au *** mappings of Au NDs with 2.5 um diameter ilustrate that the larger SERS enhancements exist in the rim of NDs which has good agreement with the electric field simulation *** SERE enhancement factors of fluorescein obtained from Au NDs/graphene substrates shows an improvement factor of 500%in comparison of graphene *** calculated SERS enhancement factors of graphene/Au NHs achieve 1,200%in comparison of graphene/planar Au film substrate.

关键词： graphene surface-enhanced Raman scattring(SERS) Au nano-discs(NDs) Au nanoholes(NHs) periodic

Electrostatic interactions in twisted bilayer graphene

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Nano Materials Science 2022年第1期4卷 27-35页

作者： Tommaso Cea Pierre A.Pantaleón Niels R.Walet Francisco Guinea imdea nanoscience Faraday 928015MadridSpain Department of Physics and Astronomy University of ManchesterManchesterM13 9PYUK Donostia International Physics Center Paseo Manuel de Lardizabal 420018San SebastianSpain

The effects of the long range electrostatic interaction in twisted bilayer graphene are described using the HartreeFock approximation. The results show a significant dependence of the band widths and shapes on electron filling,and the existence of broken symmetry phases at many densities, either valley/spin polarized, with broken sublattice symmetry, or both.

关键词： Graphene Twisted Interactions

Efficient Nanostructuring of Isotropic Gas-Atomized MnAl Powder by Rapid Milling(30s)

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Engineering 2020年第2期6卷 173-177页

作者： J.Rial E.M.Palmero A.Bollero Division of Permanent Magnets and Applications IMDEA NanoscienceCampus Universidad Autonoma de MadridMadrid 28049Spain

An unprecedentedly short milling time of 30 s was applied to gas-atomized MnAl powder in order to develop permanent magnet properties and,in particular,*** is shown that such a short processing time followed by annealing results in efficient nanostructuring and controlled phase *** defects resulting from the microstrain induced during milling,together with the creation of the bphase during post-annealing,act as pinning centers resulting in an enhanced *** study shows the importance of finding a balance between the formation of the ferromagnetic s-MnAl phase and the bphase in order to establish a compromise between magnetization and coercivity.A coercivity as high as 4.2 kOe(1 Oe=79.6 A·m^-1)was obtained after milling(30 s)and annealing,which is comparable to values previously reported in the literature for milling times exceeding 20 *** reduction of the postannealing temperature by 75℃ for the as-milled powder and a 2.5-fold increase in coercivity,while maintaining practically unchanged the remanence of the annealed gas-atomized material,opens a new path for the synthesis of isotropic MnAl-based powder.

关键词： Permanent magnets(PMs) Nanostructuring Phase transformation MnAl Gas atomization Ball milling

An atomistic approach for the structural and electronic properties of twisted bilayer graphene-boron nitride heterostructures

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npj Computational Materials 2022年第1期8卷 687-696页

作者： Min Long Pierre A.Pantaleón Zhen Zhan Francisco Guinea JoseÁngel Silva-Guillén Shengjun Yuan Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education and School of Physics and Technology Wuhan UniversityWuhan430072China imdea nanoscience C/Faraday 928015MadridSpain Donostia International Physics Center Paseo Manuel de Lardizábal 420018San SebastiánSpain Ikerbasque Basque Foundation for Science48009BilbaoSpain Wuhan Institute of Quantum Technology Wuhan430206China

Twisted bilayer graphene(TBG)has taken the spotlight in the condensed matter community since the discovery of correlated *** this work,we study heterostructures of TBG and hexagonal boron nitride(hBN)using an atomistic tight-binding model together with semi-classical molecular dynamics to consider relaxation *** hBN substrate has significant effects on the band structure of TBG even in the case where TBG and hBN are not ***,the substrate induces a large mass gap and strong pseudo-magnetic fields that break the layer ***,such degeneracy can be recovered with a second hBN ***,we develop a continuum model that describes the tight-binding band *** results show that a real-space tight-binding model in combination with semi-classical molecular dynamics is a powerful tool to study the electronic properties of moiréheterostructures,and to explain experimental results in which the effect of the substrate plays an important role.

关键词： boron electronic twisted

Spatial Raman mapping investigation of SERS performance related to localized surface plasmons

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Nano Research 2020年第1期13卷 138-144页

作者： Yansheng Liu Feng Luo imdea nanoscience Faraday 9Ciudad Universitaria de Cantoblanco28049MadridSpain School of Science Universidad Autónoma de MadridCiudad Universitaria de Cantoblanco28049MadridSpain

In this research,it reported a novel three-dimensional(3D)metallic hybrid system by introducing single-layer graphene(SLG)between silver nanoparticles(NPs)and silver nano-discs(NDs)arrays(Ag NPs/SLG/Ag NDs).By combining the plasmonic metallic nanostructures and the unique physical/chemical properties of graphene,Ag NPs/SLG/Ag NDs hybrid substrate was fabricated,and it exhibited extremely high surface-enhanced Raman scattering(SERS)*** tuning the diameter of Ag NDs,the SERS performance of Ag NPs/SLG/Ag NDs hybrid substrate has been systematically *** detection limit for rhodamine 6g(R6G)could reach the concentrations as low as 1×10^−12 mol/L,and the average enhancement factor(EF)of the Ag NPs/SLG/Ag NDs substrate could reach 5.65×10^*** advantages indicated that the Ag NPs/SLG/Ag NDs hybrid substrate could be regarded as a candidate for organic molecules detection under extremely low ***,spatial Raman mapping of Ag NPs/SLG/Ag NDs with 2.5μm diameter NDs showed the larger SERE signal existed around the rim of Ag NDs which was related to the localized surface *** phenomenon was contributed by a larger electromagnetic field which was tuned by Ag NPs and the edge of Ag *** mechanism also has been confirmed by the electromagnetic simulation result.

关键词： surface-enhanced Raman scattering(SERS) graphene high performance plasmon mapping

Stepwise magnetization reversal of geometrically tuned in diameter Ni and FeCo bi-segmented nanowire arrays

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Nano Research 2019年第7期12卷 1547-1553页

作者： Ester M. Palmero Miguel Mendez Silvia Gonzalez Cristina Bran Victor Vega Manuel Vazquez Victor M. Prida Institute of Materials Science of Madrid (ICMM-CSIC) Madrid 28049Spain Department of Physics University of OviedoFederico Garda Lorca 18Oviedo 33007Spain Division of Permanent Magnets and Applications IMDEA NanoscienceMadrid 28049Spain

Magnetization reversal processes of hexagonal dense arrays of bi-segmented Ni and Fe50Co50 nanowires consisting of two well defined diameters (45 and 80 nm) have been *** nanowires were grown inside of tailored pores of anodic alumina templates by combined anodization,atomic layer deposition (ALD) and electrodeposition *** experiments have allowed to identify their two-step magnetization reversal process ascribed to the respective segments of different *** is concluded from the differential susceptibility observed in the hysteresis loops,contrary to those for nanowires with homogeneous *** results are also confirmed by the first-order reversal curve (FORC) distribution diagrams,where an elongation parallel to the interaction axis around two coercive field values is obtained,which is correlated to the difference in diameter of the two *** well-defined two-step magnetization reversal process through the nanowire diameter design is thought to be very useful for the advanced control of the remagnetization in arrays of magnetic multidomain systems.

关键词： Bi-segmented nanowires nickel iron cobalt alloy stepwise magnetization reversal first-order reversal curve (FORC)

Rare-earth-incorporated low-dimensional chalcogenides: Dry-method syntheses and applications

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InfoMat 2020年第3期2卷 466-482页

作者： Zheshan Zhang Hongyang Zhao Chao Zhang Feng Luo Yaping Du Tianjin Key Lab for Rare Earth Materials and Applications Center for Rare Earth and Inorganic Functional MaterialsSchool of Materials Science and EngineeringNational Institute for Advanced MaterialsNankai UniversityTianjinChina imdea nanoscience MadridSpain

Chalcogenide thin films incorporating rare-earth (RE) elements with applicationsin optics, electronics, and magnetics have received considerable *** at growing pure chalcogenides, dry-method syntheses have beendeveloped. In this review, we summarize the progress thus far on lowdimensionalRE-based chalcogenides (RECs), covering fabrication methods,structures, and applications. This review also provides the summary and perspectivesof the challenges of fabrication and opportunities on the applicationof RECs in the future.

关键词： chalcogenide dry-method synthesis rare earth elements

CeO_(2)with diverse morphologies-supported IrOx nanocatalysts for efficient oxygen evolution reaction—Commemorating the 100th anniversary of the birth of Academician Guangxian Xu

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Journal of Rare Earths 2021年第4期39卷 357-363页

作者： Qingqing Li Zhichao Zeng Xiaolei Sun Feng Luo Yaping Du Tianjin Key Lab for Rare Earth Materials and Applications Center for Rare Earth and Inorganic Functional MaterialsSchool of Materials Science and EngineeringNational Institute for Advanced MaterialsNankai UniversityTianjin 300350China imdea nanoscience Faraday 9Ciudad Universitaria de CantoblancoMadrid28049Spain

IrOx-based catalysts are considered the most promising candidates for oxygen evolution reaction(OER)due to their high ***,improving their intrinsic catalytic activity is essential for practical *** this work,CeO_(2)with three different morphologies(rod,cube,octahedron)and supported IrOx nanoparticles were fabricated,and they display morphology-dependent OER *** IrOx/CeO_(2)-rod shows the highest activity;the catalysts have a catalytic activity sequence of rod>cube>octahedron.A plausible mechanism was proposed:the CeO_(2)support with different morphologies modulates the electronic structure of IrOx by the synergistic interaction promoted by oxygen vacancies between the active component and the support,thereby altering the catalytic activity of the IrOx/CeO_(2)catalyst.

关键词： IrOx/CeO_(2)catalyst Oxygen evolution reaction Morphology effect Oxygen vacancy Rare earths

Carbon nanodots:a new precursor to achieve reactive nanoporous HOPG surfaces

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Nano Research 2020年第12期13卷 3425-3432页

作者： Cristina Gutiérrez-Sánchez Emiliano Martínez-Periñán Carlos Busó-Rogero Mónica Revenga-Parra Félix Pariente Encarnación Lorenzo Departamento de Química Analítica y Análisis Instrumental Universidad Autónoma de MadridCampus de CantoblancoMadrid28049Spain Institute for Advanced Research in Chemical Sciences(IAdChem) Universidad Autónoma de MadridCampus de CantoblancoMadrid28049Spain imdea-nanoscience.Faraday 9 Campus Cantoblanco-UAMMadrid28049Spain

In the present work we develop an electrochemical assisted method to form nanopores on the surface of highly oriented pyrolytic graphite(HOPG),which was accomplished by a simple electrochemical route and a scalable nanomaterial,carbon nanodots,without applying high voltages,high temperatures or toxic *** electrodes are in a solution of N-enrich carbon nanodots in acidic media and the potential scans applied on HOPG lead to the formation of a spatially inhomogeneous porous *** diameter of the resulting nanopores can be tuned by controlling the number of electrochemical reduction *** resulting nanoporous surfaces are characterized by atomic force microscopy,Raman spectroscopy,scanning electrochemical microscopy,electrochemical impedance spectroscopy and *** nanoporous HOPG showed high *** the potential of these surfaces to the development of energy storage devices is demonstrated.

关键词： nanoporous highly oriented pyrolytic graphite(HOPG) carbon nanodots supercapacitor

Fast and reliable identification of atomically thin layers of TaSe2 crystals

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Nano Research 2013年第3期6卷 191-199页

作者： Andres Castellanos-Gomez Efren Navarro-Moratalla Guillermo Mokry Jorge Quereda Elena Pinilla-Cienfuegos Nicolas Agrait Herre S. J. van der Zant Eugenio Coronado Gary A. Steele Gabino Rubio-Bollinger Kavli Institute of nanoscience Delft University of Technology Lorentzweg 1 2628 CJ Delft The Netherlands Instituto Ciencia Molecular (ICMol) Univ. Valencia C/Catedrdtico Jose Beltrdn 2 E-46980 Paterna Spain Departamento de Fisica de la Materia Condensada (C-III). UniversidadAutonoma de Madrid Campus de Cantoblanco 28049 Madrid Spain Instituto Madrileno de Estudios Avanzados en Nanociencia imdea-Nanociencia E-28049 Madrid Spain

Deposition of clean and defect-free atomically thin two-dimensional crystalline flakes on surfaces by mechanical exfoliation of layered bulk materials has proven to be a powerful technique, but it requires a fast, reliable and non-destructive way to identify the atomically thin flakes among a crowd of thick flakes. In this work, we provide general guidelines to identify ultrathin flakes of TaSe2 by means of optical microscopy and Raman spectroscopy. Additionally, we determine the optimal substrates to facilitate the optical identification of atomically thin TaSe2 crystals. Experimental realization and isolation of ultrathin layers of TaSe2 enables future studies on the role of the dimensionality in interesting phenomena such as superconductivity and charge density waves.

关键词： atomically thin layer metal dichalcogenide layered superconductor TaSe2 optical microscopy Raman spectroscopy