Suchergebnisse

Exploring the mechanism of "heroic narratives" in Chinese cinematography, the authors of this article reflect on the underlying values of contemporary society, explore the way to identify, reflect and conduct a shared national consciousness through film and television culture. As part of the study, the article analyses the genres and values of film during the Chinese reform and opening up period to understand "micropolitics" through "micropolitics" - cultural politics.

This article analyses the digital literary criticism, which got rid of the obsession of academic Babylon in the field of literary criticism in the 1980s and revealed a more diverse field of voice, inspiring endless possibilities of variation in the transformative stage of criticism. The advent of the Internet has created a participatory field for literary criticism and a platform to weaken the distinction between identity and power. Equality disrupts the validity of authority and the structure of the knowledge circle, which is also the reason why digital literary criticism has a certain degree of carnivalesque traits. The authors believe that literary criticism in a digital context is no longer obsessed with the confusion of history and the uncertainty of time. While capturing the pulse of globalisation, it at the same time ardently embraces the value of desire endowed by consumer culture. The article points out that Chinese literary criticism in the new era is a product of the construction of multidimensional relations in a digital context, which sheds the shackles of historical context and rushes into the age of digitalisation. With the rapid flow of consumption, a very open, inclusive, and complex space of media discourse has emerged. The results of the study show that a group of numerous critics belonging to the postmodernist perspective is forming in the digital world. The authors conclude that in the confrontation between tradition and modernity, in the complex interweaving of elitist consciousness and mass consumption, in the struggle for discursive position between media and literature, digital literary criticism differs from traditional in terms of aesthetic standards, criticism style, criticism language and media platform, creating the macro future development of Chinese literary criticism with its independent attitude, revolutionary impulse and irresistible courage.

Turning graphene magnetic is a promising challenge to make it an active material for spintronics. Predictions state that graphene structures with specific shapes can spontaneously develop magnetism driven by Coulomb repulsion of π-electrons, but its experimental verification is demanding. Here, we report on the observation and manipulation of individual magnetic moments in graphene open-shell nanostructures on a gold surface. Using scanning tunneling spectroscopy, we detect the presence of single electron spins localized around certain zigzag sites of the carbon backbone via the Kondo effect. We find near-by spins coupled into a singlet ground state and quantify their exchange interaction via singlet-triplet inelastic electron excitations. Theoretical simulations picture how electron correlations result in spin-polarized radical states with the experimentally observed spatial distributions. Extra hydrogen atoms bound to radical sites quench their magnetic moment and switch the spin of the nanostructure in half-integer amounts. Our work demonstrates the intrinsic π-paramagnetism of graphene nanostructure ; We acknowledge financial support from Spanish AEI (MAT2016-78293-C6, FIS2017-83780-P, and the Maria de Maeztu Units of Excellence Program MDM-2016-0618), the Basque Government (Department of Education, Grant PI-2015-1-42), the EU project PAMS (610446), the Xunta de Galicia (Centro singular de investigación de Galicia accreditation 2016- 2019, ED431G/09), and the European Regional Development Fund (ERDF).

Turning graphene magnetic is a promising challenge to make it an active material for spintronics. Predictions state that graphene structures with specific shapes can spontaneously develop magnetism driven by Coulomb repulsion of π-electrons, but its experimental verification is demanding. Here, we report on the observation and manipulation of individual magnetic moments in graphene open-shell nanostructures on a gold surface. Using scanning tunneling spectroscopy, we detect the presence of single electron spins localized around certain zigzag sites of the carbon backbone via the Kondo effect. We find near-by spins coupled into a singlet ground state and quantify their exchange interaction via singlet-triplet inelastic electron excitations. Theoretical simulations picture how electron correlations result in spin-polarized radical states with the experimentally observed spatial distributions. Extra hydrogen atoms bound to radical sites quench their magnetic moment and switch the spin of the nanostructure in half-integer amounts. Our work demonstrates the intrinsic π-paramagnetism of graphene nanostructures ; We acknowledge financial support from Spanish AEI (MAT2016-78293-C6, FIS2017-83780-P, and the Maria de Maeztu Units of Excellence Program MDM-2016-0618), the Basque Government (Department of Education, Grant PI-2015-1-42), the EU project PAMS (610446), the Xunta de Galicia (Centro singular de investigación de Galicia accreditation 2016-2019, ED431G/09), and the European Regional Development Fund (ERDF) ; SI

We report on the construction and magnetic characterization of a fully functional hybrid molecular system composed of a single magnetic porphyrin molecule bonded to graphene nanoribbons with atomically precise contacts. We use on-surface synthesis to direct the hybrid creation by combining two molecular precursors on a gold surface. High-resolution imaging with a scanning tunneling microscope finds that the porphyrin core fuses into the graphene nanoribbons through the formation of new carbon rings at chemically predefined positions. These ensure the stability of the hybrid and the extension of the conjugated character of the ribbon into the molecule. By means of inelastic tunneling spectroscopy, we prove the survival of the magnetic functionality of the contacted porphyrin. The molecular spin appears unaffected by the graphenoid electrodes, and we simply observe that the magnetic anisotropy appears modified depending on the precise structure of the contacts. ; We acknowledge the financial support from Spanish Agencia Estatal de Investigación (AEI) (project nos. MAT2016-78293-C6 and FIS2015-62538-ERC, and the Maria de Maeztu Units of Excellence Programme MDM-2016-0618), the Basque Government (Department Industry, grant no. PI-2015-1-42), the European project PAMS (610446), the Xunta de Galicia (Centro singular de investigación de Galicia accreditation 2016 to 2019, ED431G/09), the European Research Council (grant agreement no. 635919), and the European Regional Development Fund. A ; Peer reviewed

We report on the construction and magnetic characterization of a fully functional hybrid molecular system composed of a single magnetic porphyrin molecule bonded to graphene nanoribbons with atomically precise contacts. We use on-surface synthesis to direct the hybrid creation by combining two molecular precursors on a gold surface. High-resolution imaging with a scanning tunneling microscope finds that the porphyrin core fuses into the graphene nanoribbons through the formation of new carbon rings at chemically predefined positions. These ensure the stability of the hybrid and the extension of the conjugated character of the ribbon into the molecule. By means of inelastic tunneling spectroscopy, we prove the survival of the magnetic functionality of the contacted porphyrin. The molecular spin appears unaffected by the graphenoid electrodes, and we simply observe that the magnetic anisotropy appears modified depending on the precise structure of the contacts. ; We acknowledge the financial support from Spanish Agencia Estatal de Investigación (AEI) (project nos. MAT2016-78293-C6 and FIS2015-62538-ERC, and the Maria de Maeztu Units of Excellence Programme MDM-2016-0618), the Basque Government (Department Industry, grant no. PI-2015-1-42), the European project PAMS (610446), the Xunta de Galicia (Centro singular de investigación de Galicia accreditation 2016 to 2019, ED431G/09), the European Research Council (grant agreement no. 635919), and the European Regional Development Fund ; SI

Trabajo presentado al Symposium on Surface Science (3S), celebrado en Austria del 1 al 7 de marzo de 2020. ; Support by the European Union FET Open project SPRING (grant 863098) and by the Spanish Ministry of Economy and Competitiveness, MINECO (grants FIS2017-83780-P and MAT2016-78293-C6). ; Peer reviewed

Graphene nanoribbons (GNRs), low-dimensional platforms for carbon-based electronics, show the promising perspective to also incorporate spin polarization in their conjugated electron system. However, magnetism in GNRs is generally associated with localized states around zigzag edges, difficult to fabricate and with high reactivity. Here we demonstrate that magnetism can also be induced away from physical GNR zigzag edges through atomically precise engineering topological defects in its interior. A pair of substitutional boron atoms inserted in the carbon backbone breaks the conjugation of their topological bands and builds two spin-polarized boundary states around them. The spin state was detected in electrical transport measurements through boron-substituted GNRs suspended between the tip and the sample of a scanning tunneling microscope. First-principle simulations find that boron pairs induce a spin 1, which is modified by tuning the spacing between pairs. Our results demonstrate a route to embed spin chains in GNRs, turning them into basic elements of spintronic devices. ; We gratefully acknowledge financial support from Spanish Agencia Estatal de Investigación (AEI) (MAT2016-78293, PID2019-107338RB, FIS2017-83780-P, and the Maria de Maeztu Units of Excellence Programme MDM-2016-0618), from the European Union (EU) through Horizon 2020 (FET-Open project SPRING Grant. No. 863098), the Basque Departamento de Educación through the PhD fellowship No. PRE_2019_2_0218 (S.S.), the Xunta de Galicia (Centro de Investigación de Galicia accreditation 2019–2022, ED431G 2019/03), the University of the Basque Country (Grant IT1246-19), and the European Regional Development Fund (ERDF). I. P. also thanks Xunta de Galicia and European Union (European Social Fund, ESF) for the award of a predoctoral fellowship- ; Peer reviewed

Precise control over the size and shape of graphene nanostructures allows engineering spin-polarized edge and topological states, representing a novel source of non-conventional π-magnetism with promising applications in quantum spintronics. A prerequisite for their emergence is the existence of robust gapped phases, which are difficult to find in extended graphene systems. Here we show that semi-metallic chiral GNRs (chGNRs) narrowed down to nanometer widths undergo a topological phase transition. We fabricated atomically precise chGNRs of different chirality and size by on surface synthesis using predesigned molecular precursors. Combining scanning tunneling microscopy (STM) measurements and theory simulations, we follow the evolution of topological properties and bulk band gap depending on the width, length, and chirality of chGNRs. Our findings represent a new platform for producing topologically protected spin states and demonstrate the potential of connecting chiral edge and defect structure with band engineering. ; We gratefully acknowledge financial support from the Agencia Estatal de Investigación (AEI) through projects No MAT2016-78293, PID2019-107338RB, and FIS2017-83780-P, and the Maria de Maeztu Units of Excellence Programme MDM-2016-0618, from the Xunta de Galicia (Centro singular de investigación de Galicia, accreditation 2016–2019, ED431G/09), from the University of the Basque Country (Grant IT1246-19) and the Basque Departamento de Educación (PhD scholarship no. PRE_2019_2_0218 of S.S.), and from the European Regional Development Fund. We also acknowledge funding from the European Union (EU) H2020 program through the ERC (grant agreement No. 635919) and FET Open project SPRING (grant agreement No. 863098). ; Peer reviewed

We report the energy level alignment evolution of valence and conduction bands of armchair-oriented graphene nanoribbons (aGNR) as their band gap shrinks with increasing width. We use 4,4″-dibromo-para-terphenyl as the molecular precursor on Au(111) to form extended poly-para-phenylene nanowires, which can subsequently be fused sideways to form atomically precise aGNRs of varying widths. We measure the frontier bands by means of scanning tunneling spectroscopy, corroborating that the nanoribbon's band gap is inversely proportional to their width. Interestingly, valence bands are found to show Fermi level pinning as the band gap decreases below a threshold value around 1.7 eV. Such behavior is of critical importance to understand the properties of potential contacts in GNR-based devices. Our measurements further reveal a particularly interesting system for studying Fermi level pinning by modifying an adsorbate's band gap while maintaining an almost unchanged interface chemistry defined by substrate and adsorbate. ; The project leading to this publication has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 635919), from the European Union FP7 FET-ICT "Planar Atomic and Molecular Scale devices" (PAMS) project (Contract No. 610446), from the Spanish Ministry of Economy, Industry and Competitiveness (MINECO, Grant No. MAT2016-78293-C6), from the Basque Department of Education (PI-2016-1-0027), and from the University of Padova (Grant CPDA154322, Project AMNES). ; Peer Reviewed

We report the on-surface synthesis of 7-armchair graphene nanoribbons (7-AGNRs) substituted with nitrile (CN) functional groups. The CN groups are attached to the GNR backbone by modifying the 7-AGNR precursor. Whereas many of these groups survive the on-surface synthesis, the reaction process causes the cleavage of some CN from the ribbon backbone and the on-surface cycloisomerization of few nitriles onto pyridine rings. Scanning tunneling spectroscopy and density functional theory reveal that CN groups behave as very efficient n-dopants, significantly downshifting the bands of the ribbon and introducing deep impurity levels associated with the nitrogen electron lone pairs. ; This work was supported by FP7 FET-ICT "Planar Atomic and Molecular Scale devices" (PAMS) project (funded by the European Commission under Contract No. 610446), by the Agencia Estatal de Investigacion (Cooperative Grant No. MAT2016-78293 and Grant FIS2015-62538-ERC), the Basque Government (Dep. de Educacion and UPV/EHU, Grant No. IT-756-13, and Dep. Industry, Grant PI_2015_1_42), the Xunta de Galicia (Centro singular de investigacion de Galicia accreditation 2016−2019, ED431G/09), and the European Regional Development Fund (ERDF). ; Peer Reviewed

Recent advances in graphene-nanoribbon-based research have demonstrated the controlled synthesis of chiral graphene nanoribbons (chGNRs) with atomic precision using strategies of on-surface chemistry. However, their electronic characterization, including typical figures of merit like band gap or frontier band's effective mass, has not yet been reported. We provide a detailed characterization of (3,1)-chGNRs on Au(111). The structure and epitaxy, as well as the electronic band structure of the ribbons, are analyzed by means of scanning tunneling microscopy and spectroscopy, angle-resolved photoemission, and density functional theory. ; The project leading to this publication has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement no. 635919), from the Spanish Ministry of Economy, Industry and Competitiveness (MINECO, grant nos. MAT2016-78293-C6, FIS2015-62538-ERC), from the Basque Government (grant nos. IT-621-13, PI-2015-1-42, PI-2016-1-0027), from the European Commission in FP7 FET-ICT "Planar Atomic and Molecular Scale Devices (PAMS) project (contract no. 610446), from the Xunta de Galicia (Centro singular de investigacion de Galicia accreditation 2016−2019, ED431G/09), and from the European Regional Development Fund (ERDF). ; Peer reviewed

This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes ; Recent advances in graphene-nanoribbon-based research have demonstrated the controlled synthesis of chiral graphene nanoribbons (chGNRs) with atomic precision using strategies of on-surface chemistry. However, their electronic characterization, including typical figures of merit like band gap or frontier band's effective mass, has not yet been reported. We provide a detailed characterization of (3,1)-chGNRs on Au(111). The structure and epitaxy, as well as the electronic band structure of the ribbons, are analyzed by means of scanning tunneling microscopy and spectroscopy, angle-resolved photoemission, and density functional theory ; The project leading to this publication has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement no. 635919), from the Spanish Ministry of Economy, Industry and Competitiveness (MINECO, grant nos. MAT2016-78293-C6, FIS2015-62538-ERC), from the Basque Government (grant nos. IT-621-13, PI-2015-1-42, PI-2016-1-0027), from the European Commission in FP7 FET-ICT "Planar Atomic and Molecular Scale Devices" (PAMS) project (contract no. 610446), from the Xunta de Galicia (Centro singular de investigación de Galicia accreditation 2016−2019, ED431G/09), and from the European Regional Development Fund (ERDF)