检索结果-内蒙古大学图书馆

Local symmetry theory of resonator structures for the real-space control of edge states in binary aperiodic chains

Physical Review B 2019年第21期99卷 214201-214201页

作者： M. Röntgen C. V. Morfonios R. Wang L. Dal Negro P. Schmelcher Zentrum für optische Quantentechnologien Universität Hamburg Luruper Chaussee 149 22761 Hamburg Germany Department of Electrical and Computer Engineering and Photonics Center Boston University Boston Massachusetts 02215 USA Department of Physics Boston University Boston Massachusetts 02215 USA Department of Material Science and Engineering Boston University Boston Massachusetts 02215 USA The Hamburg Centre for Ultrafast Imaging Universität Hamburg Luruper Chaussee 149 22761 Hamburg Germany

We propose a real-space approach explaining and controlling the occurrence of edge-localized gap states between the spectral quasibands of binary tight binding chains with deterministic aperiodic long-range order. The framework is applied to the Fibonacci, Thue-Morse, and Rudin-Shapiro chains, representing different structural classes. Our approach is based on an analysis of the eigenstates at weak intersite coupling, where they are shown to generically localize on locally reflection-symmetric substructures, which we call local resonators. A perturbation theoretical treatment demonstrates the local symmetries of the eigenstates. Depending on the degree of spatial complexity of the chain, the proposed local resonator picture can be used to predict the occurrence of gap-edge states even for stronger couplings. Moreover, we connect the localization behavior of a given eigenstate to its energy, thus providing a quantitative connection between the real-space structure of the chain and its eigenvalue spectrum. This allows for a deeper understanding, based on local symmetries, of how the energy spectra of binary chains are formed. The insights gained allow for a systematic analysis of aperiodic binary chains and offers a pathway to control structurally induced edge states.

关键词： Surface states 1-dimensional systems Disordered systems Quasicrystals Discrete symmetries Perturbation theory

来源：评论

学校读者我要写书评

暂无评论

Erratum: “Two-dimensional porous graphitic carbon nitride C6N7 monolayer: First-principles calculations” [Appl. Phys. Lett. 119, 142102 (2021)]

引用

Applied Physics Letters 2022年第18期120卷

作者： A. Bafekry M. Faraji M. M. Fadlallah I. Abdolhosseini Sarsari H. R. Jappor S. Fazeli M. Ghergherehchi 1Department of Radiation Application Shahid Beheshti University Tehran Iran 2Micro and Nanotechnology Graduate Program TOBB University of Economics and Technology Sogutozu Caddesi No 43 Sogutozu 06560 Ankara Turkey 3Department of Physics Faculty of Science Benha University 13518 Benha Egypt 4Department of Physics Isfahan University of Technology Isfahan 84156-83111 Iran 5Department of Physics College of Education for Pure Sciences University of Babylon Hilla Iraq 6Department of Material Science and Engineering Sharif University of Technology PO Box 11155-9466 Tehran Iran 7Department of Electrical and Computer Engineering Sungkyunkwan University 16419 Suwon South Korea

The original article1 contains misprints in the values of the elastic parameters. The values of C11 = 258.6 GPa, C22 = 290.8 GPa, and C12 = 70.73 GPa and C13 =

关键词：

来源：评论

学校读者我要写书评

暂无评论

Optical data transmission at 44 Terabits/s with a 49GHz Kerr soliton crystal microcomb

TechRxiv

引用

TechRxiv 2020年

作者： Tan, Mengxi Corcoran, Bill Xu, Xingyuan Wu, Jiayang Boes, Andreas Nguyen, Thach G. Chu, Sai T. Little, Brent E. Morandotti, Roberto Mitchell, Arnan Moss, David J. Optical Sciences Centre Swinburne University of Technology HawthornVIC3122 Australia Dept. of Electrical and Computer Systems Engineering Monash University ClaytonVIC3800 Australia School of Engineering RMIT University MelbourneVIC3001 Australia Department of Physics and Material Science City University of Hong Kong Tat Chee Avenue Hong Kong Xi’an Institute of Optics and Precision Mechanics Precision Mechanics of CAS Xi’an China INRS-Énergie Matériaux et Télécommunications 1650 Boulevard Lionel-Boulet VarennesQCJ3X 1S2 Canada

We report world record high data transmission over standard optical fiber from a single optical source. We achieve a line rate of 44.2 Terabits per second (Tb/s) employing only the C-band at 1550nm, resulting in a spectral efficiency of 10.4 bits/s/Hz. We use a new and powerful class of micro-comb called soliton crystals that exhibit robust operation and stable generation as well as a high intrinsic efficiency that, together with an extremely low spacing of 48.9 GHz enables a very high coherent data modulation format of 64 QAM. We achieve error free transmission across 75 km of standard optical fiber in the lab and over a field trial with a metropolitan optical fiber network. This work demonstrates the ability of optical micro-combs to exceed other approaches in performance for the most demanding practical optical communications applications. © 2020, CC BY.

关键词： Optical fibers

来源：评论

学校读者我要写书评

暂无评论

Photonic RF and microwave channelizer based on a Kerr soliton crystal micro-comb

TechRxiv

引用

TechRxiv 2020年

作者： Tan, Mengxi Xu, Xingyuan Wu, Jiayang Boes, Andreas Corcoran, Bill Nguyen, Thach G. Chu, Sai T. Little, Brent E. Morandotti, Roberto Mitchell, Arnan Moss, David J. Optical Sciences Centre Swinburne University of Technology HawthornVIC3122 Australia Dept. of Electrical and Computer Systems Engineering Monash University ClaytonVIC3800 Australia School of Engineering RMIT University MelbourneVIC3001 Australia Department of Physics and Material Science City University of Hong Kong Tat Chee Avenue Hong Kong Hong Kong Xi’an Institute of Optics and Precision Mechanics Precision Mechanics of CAS Xi’an China INRS-Énergie Matériaux et Télécommunications 1650 Boulevard Lionel-Boulet VarennesQCJ3X 1S2 Canada

We report a 92 channel RF channelizer based on a 48.9 GHz integrated micro-comb that operates via soliton crystals, together with a passive high-Q ring resonator that acts as a periodic filter with an optical 3dB bandwidth of 121.4 MHz. We obtain an instant RF bandwidth of 8.08 GHz and 17.55 GHz achieved through temperature tuning. These results represent a major advance to achieving fully integrated photonic RF spectrum channelizers with reduced low complexity, size, and high performance for digital-compatible signal detection and broadband analog signal processing. © 2020, CC BY.

关键词： Microwave photonics

来源：评论

学校读者我要写书评

暂无评论

Fast spiking of a mott VO2-carbon nanotube composite device

arXiv

引用

arXiv 2019年

作者： Bohaichuk, Stephanie M. Kumar, Suhas Pitner, Greg McClellan, Connor J. Jeong, Jaewoo Samant, Mahesh G. Philip Wong, H.-S. Parkin, Stuart S.P. Stanley Williams, R. Pop, Eric Stanford University Electrical Engineering StanfordCA94305 United States Hewlett Packard Labs 1501 Page Mill Rd Palo AltoCA94304 United States IBM Almaden Research Center 650 Harry Road San JoseCA95120 United States Texas A&M University Electrical & Computer Engineering College StationTX77843 United States Stanford University Material Science & Engineering StanfordCA94305 United States

The recent surge of interest in brain-inspired computing and power-efficient electronics has dramatically bolstered development of computation and communication using neuron-like spiking signals. Devices that can produce rapid and energy-efficient spiking could significantly advance these applications. Here we demonstrate DC-current or voltage-driven periodic spiking with sub-20 ns pulse widths from a single device composed of a thin VO2 film with a metallic carbon nanotube as a nanoscale heater. Compared with VO2-only devices, adding the nanotube heater dramatically decreases the transient duration and pulse energy, and increases the spiking frequency, by up to three orders of magnitude. This is caused by heating and cooling of the VO2 across its insulator-metal transition being localized to a nanoscale conduction channel in an otherwise bulk medium. This result provides an important component of energy-efficient neuromorphic computing systems, and a lithography-free technique for power-scaling of electronic devices that operate via bulk mechanisms. Copyright © 2019, The Authors. All rights reserved.

关键词： Vanadium dioxide

来源：评论

学校读者我要写书评

暂无评论

Low resistivity and high breakdown current density of 10-nm diameter van der waals tase3nanowires by chemical vapor deposition

arXiv

引用

arXiv 2019年

作者： Empante, Thomas A. Martinez, Aimee Wurch, Michelle Zhu, Yanbing Geremew, Adane K. Yamaguchi, Koichi Isarraraz, Miguel Rumyantsev, Sergey Reed, Evan J. Balandin, Alexander A. Bartels, Ludwig Department of Chemistry and Material Science & Engineering Program University of California - Riverside RiversideCA92521 United States Department of Materials Science and Engineering Stanford University StanfordCA94304 United States Nano-Device Laboratory Department of Electrical and Computer Engineering University of California RiversideCA92521 United States Center for Terahertz Research and Applications Institute of High Pressure Physics Polish Academy of Sciences Warsaw01-142 Poland

Micron-scale single-crystal nanowires of metallic TaSe3, a material that forms -Ta-Se3-TaSe3- stacks separated from one another by a tubular van der Waals (vdW) gap, have been synthesized using chemical vapor deposition (CVD) on a SiO2/Si substrate, in a process compatible with semiconductor industry requirements. Their electrical resistivity was found unaffected by downscaling from the bulk to as little as 7 nm in width and height, in striking contrast to the resistivity of copper for the same dimensions. While the bulk resistivity of TaSe3is substantially higher than that of bulk copper, at the nanometer scale the TaSe3wires become competitive to similar-sized copper ones. Moreover, we find that the vdW TaSe3nanowires sustain current densities in excess of 108A/cm2and feature an electromigration energy barrier twice that of copper. The results highlight the promise of quasi-onedimensional transition metal trichalcogenides for electronic interconnect applications and the potential of van der Waals materials for downscaled electronics. Copyright © 2019, The Authors. All rights reserved.

关键词： Van der Waals forces

来源：评论

学校读者我要写书评

暂无评论

Metal/P-type GeSn Contacts with Specific Contact Resistivity down to 4.4×10−10 Ω-cm2

Metal/P-type GeSn Contacts with Specific Contact Resistivity...

引用

Symposium on VLSI Technology

作者： Ying Wu Wei Wang Saeid Masudy-Panah Yang Li Kaizhen Han Liuhuiquan He Zheng Zhang Dian Lei Shengqiang Xu Yuye Kang Xiao Gong Yee-Chia Yeo Department of Electrical and Computer Engineering National University of Singapore (NUS) Singapore Institute of Material Research and Engineering A*STAR (Agency for Science Technology and Research) Singapore

Ga and Sn surface-segregated p + -GeSn (Seg. p + -GeSn) was grown by molecular beam epitaxy (MBE) to achieve an average active Ga doping concentration of 3.4×10 20 cm -3 and surface Sn composition of more than 8%. This enables the realization of record-low specific contact resistivity ρ c down to 4.4×10 -10 Ω-cm 2 . The average ρ c extracted from 14 sets of Ti/Seg. p + -GeSn Nano-TLM test structures, a collection of more than 90 devices is 6.5×10 -10 Ω-cm 2 . This is also the lowest ρ c for non-laser-annealed contacts. Ti contacts to p + -GeSn films with and without Ga and Sn surface segregation were fabricated. It is shown that the segregation of Ga and Sn at the Ti/p + -GeSn interface leads to 50% reduction in ρ c as compared with a sample without segregation.

关键词： Nanostructures Metals Doping Tunneling Voltage measurement Molecular beam epitaxial growth

来源：评论

学校读者我要写书评

暂无评论

Physics-informed neural networks for inverse problems in nano-optics and metamaterials

arXiv

引用

arXiv 2019年

作者： Chen, Yuyao Lu, Lu Karniadakis, George Em Negro, Luca Dal Department of Electrical and Computer Engineering Boston University BostonMA02215 United States Brown University Division of Applied Mathematics 170 Hope Street ProvidenceRI02912 United States Division of Material Science and Engineering Boston University BostonMA02215 United States Department of Physics Boston University BostonMA02215 United States

In this paper we employ the emerging paradigm of physics-informed neural networks (PINNs) for the solution of representative inverse scattering problems in photonic metamaterials and nano-optics technologies. In particular, we successfully apply mesh-free PINNs to the difficult task of retrieving the effective permittivity parameters of a number of finite-size scattering systems that involve many interacting nanostructures as well as multi-component nanoparticles. Our methodology is fully validated by numerical simulations based on the Finite Element Method (FEM). The development of physics-informed deep learning techniques for inverse scattering can enable the design of novel functional nanostructures and significantly broaden the design space of metamaterials by naturally accounting for radiation and finite-size effects beyond the limitations of traditional effective medium theories. Copyright © 2019, The Authors. All rights reserved.

关键词： Metamaterials

来源：评论

学校读者我要写书评

暂无评论

Control of single quantum emitters in bio-inspired aperiodic nano-photonic devices

arXiv

引用

arXiv 2020年

作者： Trojak, Oliver J. Gorsky, Sean Murray, Connor Sgrignuoli, Fabrizio Pinheiro, Felipe Arruda Park, Suk-In Song, Jin Dong Negro, Luca Dal Sapienza, Luca Department of Physics and Astronomy University of Southampton SouthamptonSO17 1BJ United Kingdom Department of Electrical & Computer Engineering Photonics Center Boston University 8 Saint Mary's St. BostonMA02215 United States Instituto de Fisica Universidade Federal do Rio de Janeiro Rio de Janeiro-RJ21941-972 Brazil Center for Opto-Electronic Materials and Devices Research Korea Institute of Science and Technology Seoul136-791 Korea Republic of Division of Material Science & Engineering Boston University 15 Saint Mary's St. BrooklineMA02446 United States Department of Physics Boston University 590 Commonwealth Ave. BostonMA02215 United States

Enhancing light-matter interactions on a chip is of paramount importance to study nano- and quantum optics effects and for the realisation of integrated devices, for instance, for classical and quantum photonics, sensing and energy harvesting applications. Engineered nano-devices enable the efficient confinement of light and, ultimately, the control of the spontaneous emission dynamics of single emitters, which is crucial for cavity quantum electrodynamics experiments and for the development of classical and quantum light sources. Here, we report on the demonstration of enhanced light-matter interaction and Purcell effects on a chip, based on bio-inspired aperiodic devices fabricated in silicon nitride and gallium arsenide. Internal light sources, namely optically-active defect centers in silicon nitride and indium arsenide single quantum dots, are used to image and characterize, by means of micro-photoluminescence spectroscopy, the individual optical modes confined by photonic membranes with Vogel-spiral geometry. By studying the statistics of the measured optical resonances, in partnership with rigorous multiple scattering theory, we observe log-normal distributions and report quality factors with values as high as 2201±443. Building on the strong light confinement achieved in this novel platform, we further investigate the coupling of single semiconductor quantum dots to the confined optical modes. Our results show cavity quantum electrodynamics effects providing strong modifications of the spontaneous emission decay of single optical transitions. In particular, thanks to the significant modification of the density of optical states demonstrated in Vogel-spiral photonic structures, we show control of the decay lifetime of single emitters with a dynamic range reaching 20. Our findings improve the understanding of the fundamental physical properties of light-emitting Vogel-spiral systems, show their application to quantum photonic devices, and form the basis for th

关键词： Quantum optics

来源：评论

学校读者我要写书评

暂无评论

One-dimensional edge contacts to a monolayer semiconductor

arXiv

引用

arXiv 2019年

作者： Jain, Achint Szabó, Áron Parzefall, Markus Bonvin, Eric Taniguchi, Takashi Watanabe, Kenji Bharadwaj, Palash Luisier, Mathieu Novotny, Lukas Photonics Laboratory ETH Zürich Zürich8093 Switzerland Integrated Systems Laboratory ETH Zürich Zürich8092 Switzerland National Institute for Material Science 1-1 Namiki Tsukuba305-0044 Japan Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States

Integration of electrical contacts into van der Waals (vdW) heterostructures is critical for realizing electronic and optoelectronic functionalities. However, to date no scalable methodology for gaining electrical access to buried monolayer two-dimensional (2D) semiconductors exists. Here we report viable edge contact formation to hexagonal boron nitride (hBN) encapsulated monolayer MoS2. By combining reactive ion etching, in-situ Ar+ sputtering and annealing, we achieve a relatively low edge contact resistance, high mobility (up to ∼30 cm2 V−1 s−1) and high on-current density (>50 µA/µm at VDS = 3 V), comparable to top contacts. Furthermore, the atomically smooth hBN environment also preserves the intrinsic MoS2 channel quality during fabrication, leading to a steep subthreshold swing of 116 mV/dec with a negligible hysteresis. Hence, edge contacts are highly promising for large-scale practical implementation of encapsulated heterostructure devices, especially those involving air sensitive materials, and can be arbitrarily narrow, which opens the door to further shrinkage of 2D device footprint. Copyright © 2019, The Authors. All rights reserved.

关键词： Monolayers

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：