Special Collection：石墨烯和其他二维材 料 近十年来，自 K. Novoselov 和 A. Geim 发现石墨烯以来，由于其引人注目的特性，致力于石墨烯和其他二维材料的研究工作如火如荼。 K. Novoselov 和 A. Geim 亦因 “ 二维材料石墨烯的开创性实验 ” 摘取 2010 年诺贝尔物理学奖。近年来对石墨烯的研究进一步激发了研究人员对于其他二维材料的极大兴趣。在石墨烯之外的这些新材料中，其直系表亲硅烯和锗（硅和锗的对应物）得到了特别关注。 这些材料的低能量理论可以由類石墨烯的狄拉克费米子哈密尔顿量所描述，因此其相对较强的自旋 - 轨道相互作用大到足以使诸如硅基和锗基的材料成为非平凡的拓扑绝缘体。 此外，对单层过渡金属二硫属元素化物和层状双过渡金属碳 / 氮化物（ MXenes ）的研究也越来越受到关注。 由诺贝尔物理学奖得主、英国曼彻斯特大学 Kostya Novoselov 教授领衔，与新加坡国立大学 Daria Andreeva 教授、中科院金属所任文才教授和北航单光存教授合作为 FOP 刊组织了专题 “Graphene and other Two-Dimensional Materials” 。这一专题涵盖 2D 材料的实验合成、实验表征（ ARPES ， STM ，光学吸收等）、电学特性、电磁微波吸收特性、光学特性、磁学特性、拓扑特性及潜在应用等方面。文章已陆续上线，将分两部分刊载。 Special Collection: Graphene and other Two-Dimensional Materials (Part I) (Eds. Daria Andreeva, Wencai Ren, Guangcun Shan Kostya Novoselov) REVIEW The rise of two-dimensional MoS 2 for catalysis Jun Mao ( 毛军 ), Yong Wang ( 王勇 ), Zhilong Zheng ( 郑智龙 ), and Dehui Deng ( 邓德会 )* Abstract: Two-dimensional (2D) MoS 2 is used as a catalyst or support and has received increased research interest because of its superior structural and electronic properties compared with those of bulk structures. In this article, we illustrate the active sites of 2D MoS 2 and various strategies for enhancing its intrinsic catalytic activity. The recent advances in the use of 2D MoS 2 –based materials for applications such as conventional heterogeneous catalysis, electrocatalysis, and photocatalysis are discussed. We also discuss the future opportunities and challenges for 2D MoS 2 –based materials, in both fundamental research and industrial applications. REVIEW Environmental engineering of transition metal dichalcogenide optoelectronics Trevor LaMountain, Erik J. Lenferink, Yen-Jung Chen, Teodor K. Stanev, and Nathaniel P. Stern* Abstract: The explosion of interest in two-dimensional van der Waals materials has been in many ways driven by their layered geometry. This feature makes possible numerous avenues for assembling and manipulating the optical and electronic properties of these materials. In the specific case of the monolayer transition metal dichalcogenide semiconductors, the direct band gap combined with the exibility for manipulation of layers has made this class of materials promising for optoelectronics. Here, we review the properties of these layered materials and the various means of engineering their properties for optoelectronics. We summarize approaches to control using their structural and chemical environment, and we give particular detail on the integration of these materials into engineered optical fields to control their optical characteristics. This combination of controllability from their layered surface structure and photonic environment provide an expansive landscape for novel optoelectronic phenomena. REVIEW Two-dimensional materials: Emerging toolkit for construction of ultrathin high-efficiency microwave shield and absorber Mingjun Hu * , Naibai Zhang, Guangcun Shan, Jiefeng Gao, Jinzhang Liu, and Robert K. Y. Li* Abstract: Two-dimensional (2D) materials generally have unusual physical and chemical properties owing to the confined electro-strong interaction in a plane and can exhibit obvious anisotropy and a significant quantum-confinement effect, thus showing great promise in many fields. Some 2D materials, such as graphene and MXenes, have recently exhibited extraordinary electromagnetic-wave shielding and absorbing performance, which is attributed to their special electrical behavior, large specific surface area, and low mass density. Compared with traditional microwave attenuating materials, 2D materials have several obvious inherent advantages. First, similar to other nanomaterials, 2D materials have a very large specific surface area and can provide numerous interfaces for the enhanced interfacial polarization as well as the reflection and scattering of electromagnetic waves. Second, 2D materials have a particular 2D morphology with ultrasmall thickness, which is not only beneficial for the penetration and dissipation of electromagnetic waves through the 2D nanosheets, giving rise to multiple reflections and the dissipation of electromagnetic energy, but is also conducive to the design and fabrication of various well-defined structures, such as layer-by-layer assemblies, core–shell particles, and porous foam, for broadband attenuation of electromagnetic waves. Third, owing to their good processability, 2D materials can be integrated into various multifunctional composites for multimode attenuation of electromagnetic energy. In addition to behaving as microwave reflectors and absorbers, 2D materials can act as impedance regulators and provide structural support for good impedance matching and setup of the optimal structure. Numerous studies indicate that 2D materials are among the most promising microwave attenuation materials. In view of the rapid development and enormous advancement of 2D materials in shielding and absorbing electromagnetic wave, there is a strong need to summarize the recent research results in this field for presenting a comprehensive view and providing helpful suggestions for future development. RESEARCH Monolayered semiconducting GeAsSe and SnSbTe with ultrahigh hole mobility Yu Guo, Nan Gao, Yizhen Bai, Jijun Zhao * , and Xiao Cheng Zeng* (Cover story) Abstract: High carrier mobility and a direct semiconducting band gap are two key properties of materials for electronic device applications. Using first-principles calculations, we predict two types of two-dimensional semiconductors, ultrathin GeAsSe and SnSbTe nanosheets, with desirable electronic and optical properties. Both the GeAsSe and SnSbTe sheets are energetically favorable, with formation energies of −0.19 and −0.09 eV/atom, respectively, and have excellent dynamical and thermal stability, as determined by phonon dispersion calculations and Born–Oppenheimer molecular dynamics simulations. The relatively weak interlayer binding energies suggest that these monolayer sheets can be easily exfoliated from the bulk crystals. Importantly, monolayer GeAsSe and SnSbTe possess direct band gaps (2.56 and 1.96 eV, respectively) and superior hole mobility ( ～ 20 000 cm 2 × V −1 × s −1 ), and both exhibit notable absorption in the visible region. A comparison of the band edge positions with the redox potentials of water reveals that layered GeAsSe and SnSbTe are potential photocatalysts for water splitting. These exceptional properties make layered GeAsSe and SnSbTe promising candidates for use in future high-speed electronic and optoelectronic devices. RESEARCH Interfacial charge transfer in WS 2 monolayer/CsPbBr 3 microplate heterostructure Zhen-Zhong Yan, Zhao-Han Jiang, Jun-Peng Lu * , and Zhen-Hua Ni Abstract: Integration of heterogenous materials produces compelling physical phenomena and increased performance of optoelectronic devices. In this work, we integrate CsPbBr 3 microplate with WS 2 monolayer to investigate the interfacial carrier transfer mechanism in the heterojunction. The quenching of photoluminescence (PL) emission from CsPbBr 3 and WS 2 after heterostructure formation indicates efficient charge transfer in the junction. Low-temperature PL spectra reveal that the decreasing PL of WS 2 arises from the vanishing of biexcitons. Photodetection based on the WS 2 /CsPbBr 3 heterostructure is demonstrated. The higher performance from the junction further certifies the occurrence of charge transfer in the heterojunction. RESEARCH Vertically aligned γ-AlOOH nanosheets on Al foils as flexible and reusable substrates for NH 3 adsorption Chen Yang, Ying Chen * , Dan Liu, Jinfeng Wang, Cheng Chen, Jiemin Wang, Ye Fan, Shaoming Huang, and Weiwei Lei * Abstract: Vertically aligned γ-AlOOH nanosheets (NSs) have been successfully fabricated on flexible Al foils via a solvothermal route without morphology-directing agents. Three different reaction temperatures (25, 80, and 120 °C) and reaction times (30 min, 45 min, and 24 h) are discussed for the growth period, which efficiently tune the density and size of the γ-AlOOH NSs. Meanwhile, the growth speed of the nanosheets confirms that dominant growth stage is seen in the initial 45min. Furthermore, the interlayer of the γ-AlOOH NSs displays an average height of 140 nm and superhydrophilicity. By dynamic adsorption, the as-synthesized γ-AlOOH NSs exhibit an outstanding NH 3 adsorption capacity of up to 146 mg/g and stably excellent regeneration for 5 cycles. The mechanism of NH 3 adsorption has been explained by the Lewis acid/base theory between NH 3 molecules and in-plane of γ-AlOOH NSs. The H-bond interactions among the NH 3 molecules and the edge groups (-OH) further improve the capture ability of the nanosheets. 全文下载： http://journal.hep.com.cn/fop/EN/collection/showCollection.do?id=191 -------------------------------------------- Special Collection: Graphene and other Two-Dimensional Materials (Part II) (Eds. Daria Andreeva, Wencai Ren, Guangcun Shan Kostya Novoselov) (Coming soon) PERSPECTIVE Graphene and other two-dimensional materials Kostya Novoselov*, Daria Andreeva, Wencai Ren, and Guangcun Shan REVIEW The art of designing carbon allotropes Run-Sen Zhang and Jin-Wu Jiang* Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, China Abstract: As stimulated by the success of graphene and diamond, a variety of carbon allotropes have been discovered in recent years in either two-dimensional or three-dimensional configurations. These emerging new carbon allotropes have some quite different novel mechanical or physical properties, though they also share some common features. In this review, we comparatively survey some major properties for fifteen newly discovered carbon allotropes. By comparing their structural topology, we disclose a general routine to design most carbon allotropes from two mother structures – graphene and diamond. We also discuss several future prospects as well as the current challenges in designing new carbon allotropes. This article is part of themed collection: Graphene and other Two-Dimensional Materials (Eds. Daria Andreeva, Wencai Ren, Guangcun Shan Kostya Novoselov) REVIEW Graphene based functional devices: A short review Rong Wang, Xingang Ren, Ze Yan, Wei E.I. Sha, Li Jun Jiang*, and Guangcun Shan* Rong Wang 1 , Xin-Gang Ren 1, 2 ( ), Ze Yan 3 , Li-Jun Jiang 1 ( ), Wei E. I. Sha 4 , Guang-Cun Shan 5, 6 ( ) 1 . Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China 2 . Key Laboratory of Intelligent Computing Signal Processing, Ministry of Education, Anhui University, Hefei 230039, China 3 . School of Instrumentation Science Opto-electronics Engineering, Beihang University, Beijing 100191, China 4 . Key Laboratory of Micro-nano Electronic Devices and Smart Systems of Zhejiang Province, College of Information Science Electronic Engineering, Zhejiang University, Hangzhou 310027, China 5 . School of Instrumentation Science Opto-electronics Engineering, Beihang University, Beijing 100191, China 6 . California NanoSystem Institute and Department of Chemistry Biochemistry, University of California, Los Angeles, CA 90095, USA Abstract: Graphene is an ideal 2D material system bridging electronic and photonic devices. It also breaks the fundamental limits of electronics and photonics named speed and size, respectively. Graphene offers multiple functions of signal emission, transmission, modulation, and detection in a broad band, high speed, compact size, and low loss. Here, we will have a bird’s eye view of the graphene based functional devices at microwave, terahertz, and optical frequencies. The basic physical foundation and computational model will be discussed as well. RESEARCH Probing interlayer interactions in wse 2 -graphene heterostructures by ultralow frequency Raman spectroscopy Yue Liu ( 刘月 ), Hao Zhang ( 张昊 ) , Yu Zhou ( 周煜 ), Feirong Ran ( 冉飞荣 ), Weihao Zhao ( 赵炜昊 ), Lin Wang ( 王琳 ), Jindong Zhang ( 张锦东 ), Xiao Huang ( 黄晓 )* ( ) , Hai Li ( 李海 ) ( ) Key Laboratory of Flexible Electronics (KLOFE) Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), Nanjing 211816, China Abstract: Interlayer interactions at heterointerfaces of van der Waals heterostructures (vdWHs), which consist of vertically stacked two-dimensional (2D) materials, play important roles in determining their properties. The interlayer interactions are tunable from non-coupling to strong coupling by controlling the twist angle and distance between adjacent layers. However, the influence of stacking sequence and individual component thickness on the properties of vdWHs is rarely explored. In this work, the influence of stacking sequence of WSe 2 and graphene in vdWHs of graphene-on-WSe 2 (graphene/WSe 2 ) or WSe 2 -on-graphene (WSe 2 /graphene), as well as their thickness on their interlayer interaction was systematically investigated by ultralow frequency (ULF) Raman spectroscopy. A series of ULF breathing modes of WSe 2 nanosheets in these vdWHs were observed with frequencies highly dependent on graphene thickness. Interestingly, the ULF breathing modes of WSe 2 red shifted in both graphene/WSe 2 and WSe 2 /graphene configurations, and the amount of shift in the former is much larger than that in the latter. In contrast, no obvious ULF shift was observed by varying the twist angle between WSe 2 and graphene. This indicates that the interlayer interaction is more sensitive to the stacking sequence compared with the twist angle. Our results provide alternative approaches to modulate the interlayer interaction of vdWHs and thus tune their optical and optoelectronic properties. Stacking transition in rhombohedral graphite Tataiana Latychevskaia 1 , Seok-Kyun Son 2, 3 , Yaping Yang 2, 3 , Dale Chancellor 2, 3 , Michael Brown 2, 3 , Servet Ozdemir 2, 3 , Ivan Madan 1 , Gabriele Berruto 1 , Fabrizio Carbone 1 , Artem Mishchenko 2, 3 , Kostya S. Novoselov 2, 3 ( ) 1 . Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), école Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland 2 . National Graphene Institute, University of Manchester, Oxford Road, Manchester, M13 9PL, UK 3 . School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester, M13 9PL, UK Abstract Few-layer graphene (FLG) has recently been intensively investigated for its variable electronic properties, which are defined by a local atomic arrangement. While the most natural arrangement of layers in FLG is ABA (Bernal) stacking, a metastable ABC (rhombohedral) stacking, characterized by a relatively high-energy barrier, can also occur. When both types of stacking occur in one FLG device, the arrangement results in an in-plane heterostructure with a domain wall (DW). In this paper, we present two approaches to demonstrate that the ABC stacking in FLG can be controllably and locally turned into the ABA stacking. In the first approach, we introduced Joule heating, and the transition was characterized by 2D peak Raman spectra at a submicron spatial resolution. The transition was initiated in a small region, and then the DW was controllably shifted until the entire device became ABA stacked. In the second approach, the transition was achieved by illuminating the ABC region with a train of 790-nm-wavelength laser pulses, and the transition was visualized by transmission electron microscopy in both diffraction and dark-field imaging modes. Further, using this approach, the DW was visualized at a nanoscale spatial resolution in the dark-field imaging mode.Keywordsgraphene graphite van der Waals heterostructures domain wall Raman spectroscopy transmission electron microscopy electron diffraction structural transition REVIEW Coulomb drag and exciton condensation in graphene double-layer heterostructures Xiaomeng Liu, Jia Li, Cory dean, and Philip Kim* Abstract: This review discusses effects and phenomena caused by interlayer interaction in graphene double-layer heterostructures, where two graphene layers are separated by a thin insulator. Two interaction-driven phenomena extensively studied in semiconductor double quantum wells, Coulomb drag and exciton condensation, are introduced. Under high magnetic fields and at low temperatures, exciton condensation was observed when electrons from two layers coherently fill one Landau level. We then focus on graphene double-layer systems and discuss the fabrication as well as the unique properties and capabilities of this new platform. Theoretical proposals and experimental attempts to realize exciton condensation in graphene double-layer under zero magnetic field are reviewed. In drag experiments, unconventional drag have been observed in monolayer graphene double-layer near charge neutrality and in bilayer graphene double-layer. Mechanisms that may cause these unconventional drag effects are examined. Under strong magnetic fields, the band structure of the graphene is flattened by Landau quantization. Study of exciton condensation in this regime is presented, with emphasis on unique observations enabled by the highly tunable and strongly interacting graphene double-layer platform. Finally, we briefly discuss open questions and prospective research directions in graphene and other 2D material double-layer systems.
Nature : 物理学家设计出导电接近光速 的 二维材料 诸平 UCI physicist Jing Xia (right, with graduate student Alex Stern) calls the fiber-optic Sagnac interferometer he built the most sensitive magnetic microscope in the world. He compares it to a telescope that an ornithologist in Irvine could use to inspect the eye of a bird in New York. Credit: Steve Zylius / UCI 据 加州大学欧文分校 ( University of California, Irvine ， UCI) 2017 年 4 月 26 日 提供的消息，下面照片上的 右 边一位就是该校的 物理学家夏 晶 (Jing Xia 音译），而另一位是 研究生亚历克斯 · 斯特恩 （ Alex Stern ）， 夏 晶声称他已经 建造 出 世界上最敏感的磁力显微镜 即 光纤萨尼亚克干涉仪 （ Sagnac interferometer ） 。 将其 比作一 架在 欧文 的 鸟类学家可以用 其 来检查 纽约一只 鸟眼睛 的 望远镜。 加州大学欧文分校 ( University of California, Irvine ) 和其他地方 的 物理学家 ， 已经 制造 出 新的突破电和磁属性 的 二维量子材料 , 可以 用其来构建 未来 的 量子计算机 及其他 等先进的电子 产品 。 2017 年 4 月份，有 3 个独立的研究 已经 在本月的《自然》 （ Nature ） , 《 科学进展 》（ Science Advances ） 以及《自然材料》（ Nature Materials ） 杂志 上发表 , 美国 UCI 的研究人员 和 加州大学伯克利分校 （ UC Berkeley ）、 劳伦斯伯克利国家实验室 （ Lawrence Berkeley National Laboratory ）、 普林斯顿大学 （ Princeton University ） , 中国 复旦大学 以及美国 马里兰大学 （ University of Maryland ） 的 研究人员合作开发出 二维 态新材料后对其物理性质进行研究， 确定 它 们可以 将 计算机速度和 功率推进到 新 的 高度。 更多信息请浏览 Cheng Gong , Lin Li , Zhenglu Li , Huiwen Ji , Alex Stern , Yang Xia , Ting Cao , Wei Bao , Chenzhe Wang , Yuan Wang , Z. Q. Qiu , R. J. Cava , Steven G. Louie , Jing Xia , Xiang Zhang . Discovery of intrinsic ferromagnetism in two-dimensional van der Waals crystals . Nature , 2017 , DOI: 10.1038/nature22060 . Published online : 26 April 2017 . Abstract The realization of long-range ferromagnetic order in two-dimensional van der Waals crystals, combined with their rich electronic and optical properties, could lead to new magnetic, magnetoelectric and magneto-optic applications 1 , 2 , 3 , 4 . In two-dimensional systems, the long-range magnetic order is strongly suppressed by thermal fluctuations, according to the Mermin–Wagner theorem 5 ; however, these thermal fluctuations can be counteracted by magnetic anisotropy. Previous efforts, based on defect and composition engineering 6 , 7 , 8 , 9 , 10 , or the proximity effect, introduced magnetic responses only locally or extrinsically. Here we report intrinsic long-range ferromagnetic order in pristine Cr 2 Ge 2 Te 6 atomic layers, as revealed by scanning magneto-optic Kerr microscopy. In this magnetically soft, two-dimensional van der Waals ferromagnet, we achieve unprecedented control of the transition temperature (between ferromagnetic and paramagnetic states) using very small fields (smaller than 0.3 tesla). This result is in contrast to the insensitivity of the transition temperature to magnetic fields in the three-dimensional regime. We found that the small applied field leads to an effective anisotropy that is much greater than the near-zero magnetocrystalline anisotropy, opening up a large spin-wave excitation gap. We explain the observed phenomenon using renormalized spin-wave theory and conclude that the unusual field dependence of the transition temperature is a hallmark of soft, two-dimensional ferromagnetic van der Waals crystals. Cr 2 Ge 2 Te 6 is a nearly ideal two-dimensional Heisenberg ferromagnet and so will be useful for studying fundamental spin behaviours, opening the door to exploring new applications such as ultra-compact spintronics.
标签: 二维材料
