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Tailoring properties of hybrid perovskites by domain-width engineering with charged walls

npj Computational materials 2018年第1期4卷 26-31页

作者： Lan Chen Charles Paillard Hong Jian Zhao JorgeÍñiguez Yurong Yang Laurent Bellaiche Physics Department and Institute for Nanoscience and Engineering University of ArkansasFayettevilleArkansas 72701USA Materials Research and Technology Department Luxembourg Institute of Science and Technology(LIST)5 Avenue des Hauts-FourneauxL-4362 Esch/AlzetteLuxembourg National Laboratory of Solid State Microstructures Jiangsu Key Laboratory of Artificial Functional Materials and Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

Charged ferroelectric domain walls are fascinating electrical topological defects that can exhibit unusual ***,in the search for novel phenomena,we perform and analyze first-principles calculations to investigate the effect of domain width on properties of domains with charged walls in the photovoltaic material consisting of methylammonium lead iodide hybrid *** report that such domains are stable and have rather low domain wall energy for any investigated width(that is,up to 13 lattice constants).Increasing the domain width first linearly decreases the electronic band gap from≃1.4 eV to about zero(which therefore provides an efficient band-gap engineering),before the system undergoes an insulator-to-metal transition and then remains metallic(with both the tail-to-tail and head-to-head domain walls being conductive)for the largest *** these results can be understood in terms of:(i)components of polarization along the normal of the domain walls being small in magnitude;(ii)an internal electric field that is basically independent of the domain width;and(iii)rather negligible charge transfer between *** findings deepen the knowledge of charged ferroelectric domain walls and can further broaden their potential for applications,particularly in the context of halide perovskites for photovoltaics.

关键词： properties walls perovskite

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Soluble Covalent Organic Frameworks as Efficient Lithiophilic Modulator for High-Performance Lithium Metal Batteries

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Angewandte Chemie 2025年

作者： Dr. Shen Xu Tuoya Naren Yanwei Zhao Qianfeng Gu Ting Wai Lau Prof. Dr. Chun-Sing Lee Prof. Dr. Fu-Rong Chen Dr. Jun Yin Prof. Libao Chen Prof. Dr. Qichun Zhang Department of Materials Science and Engineering City University of Hong Kong Hong Kong SAR 999077 P. R. China State Key Laboratory of Flexible Electronics & Institute of Advanced Materials (IAM) Nanjing University of Posts & Telecommunications Nanjing 210023 P. R. China State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 P. R. China Department of Applied Physics The Hong Kong Polytechnic University Hong Kong SAR 999077 P. R. China Department of Chemistry Center of Super-Diamond and Advanced Films (COSDAF) & Hong Kong Institute of Clean Energy City University of Hong Kong Hong Kong SAR 999077 P.R. China City University of Hong Kong Shenzhen Research Institute Shenzhen 518057 P.R. China

Lithium metal batteries (LMBs) are regarded as the potential alternative of lithium-ion batteries due to their ultrahigh theoretical specific capacity (3860 mAh g −1 ). However, severe instability and safety problems caused by the dendrite growth and inevitable side reactions have hindered the commercialization of LMBs. To solve them, in this contribution, a design strategy of soluble lithiophilic covalent organic frameworks (COFs) is proposed. By introducing polyethylene glycol as the side chains, two COFs ( CityU-28 and CityU-29 ) not only become soluble for the facile coating technique, but also can facilitate the lithium-ion migration in batteries. Furthermore, when coated on the lithium anode of LMB, both COFs can act as artificial solid electrolyte interphase to prevent dendrite growth thus enabling the long-term stability of the cells. Notably, the symmetric CityU-29@Li cell can work for more than 5000 h at a current density of 2 mA cm −2 and an areal capacity of 1 mAh cm −2 . A remarkable capacity retention of 78.9 % after 1500 cycles and a Coulombic efficiency of about 99.9 % at 1.0 C can also be realized in CityU-29@Li||LiFePO 4 full cell. This work could provide a universal design strategy for soluble COFs and enlighten their application in diverse scenarios, especially energy-related fields.

关键词： artificial solid-electrolyte interphase covalent organic frameworks lithium metal battery reticular chemistry solution-processing

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Comprehensive magnetic phase diagrams of the polar metal Ca3(Ru0.95Fe0.05)2O7

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Physical Review B 2019年第22期99卷 224411-224411页

作者： Shiming Lei Shalinee Chikara Danilo Puggioni Jin Peng Mengze Zhu Mingqiang Gu Weiwei Zhao Yu Wang Yakun Yuan Hirofumi Akamatsu Moses H. W. Chan Xianglin Ke Zhiqiang Mao James M. Rondinelli Marcelo Jaime John Singleton Franziska Weickert Vivien S. Zapf Venkatraman Gopalan Department of Materials Science and Engineering and Materials Research Institute The Pennsylvania State University University Park Pennsylvania 16802 USA National High Magnetic Field Laboratory Los Alamos National Laboratory Los Alamos New Mexico 87545 USA Department of Materials Science and Engineering Northwestern University Evanston Illinois 60208 USA Department of Physics and Engineering Physics Tulane University New Orleans Louisiana 70118 USA Collaborative Innovation Center of Advanced Microstructures Laboratory of Solid State Microstructures School of Physics Nanjing University Nanjing 210093 China Department of Physics and Astronomy Michigan State University East Lansing Michigan 48824 USA Department of Physics The Pennsylvania State University University Park Pennsylvania 16802 USA Laboratory for Materials and Structures Institute of Innovative Research Tokyo Institute of Technology Yokohama 226-8503 Japan

Polar metals exist as a rather unique class of materials as they combine two seemingly mutually exclusive properties (polar order and metallicity) in one system. So far only a few polar metals have been unambiguously identified; the magnetic ones are exceptionally rare. Here we investigate a 5% Fe-doped polar metal Ca3Ru2O7, via electrical transport, magnetization, microstrain, and optical second-harmonic generation measurements. We report the full magnetic phase diagrams (in the field-temperature space) for magnetic field H∥a and H∥b, which exhibit distinct field-dependent magnetizations behavior. In particular, for H∥a we found a ferromagnetic incommensurate spin structure, which is absent in the pure Ca3Ru2O7. We propose a microscopic spin model to understand this behavior, highlighting the role of Fe doping in tipping the delicate balance of the underlying exchange-interaction energy in this system.

关键词： Magnetic order Magnetism Ferroelectrics Multiferroics Magnetization measurements Optical second-harmonic generation Resistivity measurements

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First-principles study of crystal-face specificity in surface properties of Fe-rich Fe-Cr alloys

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Physical Review materials 2019年第3期3卷 034401-034401页

作者： Xiaojie Li Stephan Schönecker Xiaoqing Li Shengzhi Hao Jijun Zhao Börje Johansson Levente Vitos Key Laboratory of Materials Modification by Laser Electron and Ion Beams (Dalian University of Technology) Ministry of Education Dalian 116024 China Applied Materials Physics Department of Materials Science and Engineering KTH-Royal Institute of Technology Stockholm SE-10044 Sweden Department of Physics and Astronomy Division of Materials Theory Uppsala University Box 516 SE-75120 Uppsala Sweden Research Institute for Solid State Physics and Optics Wigner Research Center for Physics Budapest H-1525 P.O. Box 49 Hungary

A density-functional theory investigation of the (100) and (110) surfaces of the body-centered cubic (bcc) Fe1−xbCrxb binary alloys, xb≤15 at.%, is reported. The energies and segregation energies of these surfaces were calculated for chemically homogeneous concentration profiles and for Cr surface contents deviating from the nominal one of the bulk. The implications of these results for the surface alloy phase diagram are discussed. The surface chemistry of Fe−Cr(100) is characterized by a transition from Cr depletion to Cr enrichment in a critical bulk Cr composition window of 6

关键词： Density of states Ferrimagnetism Ferromagnetism Surface & interfacial phenomena Body-centered cubic Disordered alloys Transition metal alloys Density functional calculations Korringa-Kohn-Rostoker method

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Corrections to “Watt-Level CW Ti: Sapphire Oscillator Directly Pumped With Green Laser Diodes Module” [Mar 1, 2020 247-250]

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IEEE Photonics Technology Letters 2020年第24期32卷 1543-1543页

作者： Zhang-Wang Miao Hai-Juan Yu Jing-Yuan Zhang Shu-Zhen Zou Peng-Fei Zhao Bo-Jie Lou Xue-Chun Lin Laboratory of All-Solid-State Light Sources Institute of Semiconductors Chinese Academy of Sciences Beijing China Beijing Engineering Technology Research Center of All-Solid-State Lasers Advanced Manufacturing Beijing China College of Materials Science and Opto-Electronic Technology University of the Chinese Academy of Sciences Beijing China Center of Materials Science and Optoelectronics Engineering University of the Chinese Academy of Sciences Beijing China

In the letter [1] , the authors’ affiliation were listed incorrectly. The correct affiliation is as follows:

关键词： Laser excitation Laser beams Optical pulse shaping Optical pumping Diode lasers Optical design techniques

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Tuning of the intrinsic magnetic damping parameter in epitaxial CoNi(001) films : Role of the band-filling effect

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Physical Review B 2019年第2期100卷 024403-024403页

作者： S. J. Xu J. Y. Shi Y. S. Hou Z. Zheng H. B. Zhao R. Q. Wu S. M. Zhou Z. Shi W. J. Fan Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology and Pohl Institute of Solid State Physics and School of Physics Science and Engineering Tongji University Shanghai 200092 China Shanghai Ultra-precision Optical Engineering Research Center and Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) Department of Optical Science and Engineering Fudan University Shanghai 200433 China Department of Physics and Astronomy University of California Irvine California 92697-4575 USA

The band-filling effect, which is due to tuning the electron occupation number near the Fermi level, on the intrinsic magnetic damping parameter is demonstrated by employing high-quality epitaxial Co1−xNix alloy films, in which the Fermi level and the density of states can be continuously tuned by varying the Ni concentration x. The intrinsic magnetic damping parameter, measured by the time-resolved magneto-optical Kerr effect, changes weakly at small x and increases sharply for x>0.80. The experimental results are well reproduced by the density functional theory calculation. More interestingly, the magnetic damping parameter and the density of states near the Fermi level share similar variation trends, demonstrating their correlation. The band-filling effect in 3d magnetic transition metal alloys provides a way to tune the magnetic damping parameter as a key element in the controlg of energy loss and speed of spintronic devices.

关键词： Density of states Spin dynamics Spin relaxation

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Quantum light source devices of In(Ga)As semiconductor self-assembled quantum dots

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Journal of Semiconductors 2019年第7期40卷 27-37页

作者： Xiaowu He Yifeng Song Ying Yu Ben Ma Zesheng Chen Xiangjun Shang Haiqiao Ni Baoquan Sun Xiuming Dou Hao Chen Hongyue Hao Tongtong Qi Shushan Huang Hanqing Liu Xiangbin Su Xinliang Su Yujun Shi Zhichuan Niu State Key Laboratory for Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Science Beijing 100083 China School of Engineering University of Glasgow Glasgow G12 8LT UK State Key Laboratory of Optoelectronic Materials and Technologies School of Electronics and Information Technology Sun Yat-sen University Guangzhou 510275 China Laboratory of Solid Quantum Material Center College of Physics and Electronic Engineering Shanxi University Taiyuan 030006 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 China Beijing Academy of Quantum Information Sciences Beijing 100193 China

A brief introduction of semiconductor self-assembled quantum dots (QDs) applied in single-photon sources is given. Single QDs in confined quantum optical microcavity systems are reviewed along with their optical properties and coupling characteristics. Subsequently, the recent progresses in In(Ga)As QDs systems are summarized including the preparation of quantum light sources, multiple methods for embedding single QDs into different microcavities and the scalability of single-photon emitting wavelength. Particularly, several In(Ga)As QD single-photon devices are surveyed including In(Ga)As QDs coupling with nanowires, InAs QDs coupling with distributed Bragg reflection microcavity and the In(Ga)As QDs coupling with micropillar microcavities. Furthermore, applications in the field of single QDs technology are illustrated, such as the entangled photon emission by spontaneous parametric down conversion, the single-photon quantum storage, the chip preparation of single-photon sources as well as the single-photon resonance-fluorescence measurements.

关键词： quantum optics quantum dots nanowires light sources

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Predicted lithium oxide compounds and superconducting low-pressure LiO4

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Physical Review B 2019年第14期100卷 144104-144104页

作者： Xiao Dong Jingyu Hou Jun Kong Haixu Cui Yan-Ling Li Artem R. Oganov Kuo Li Haiyan Zheng Xiang-Feng Zhou Hui-Tian Wang Key Laboratory of Weak-Light Nonlinear Photonics and School of Physics Nankai University Tianjin 300071 China College of Physics and Materials Science Tianjin Normal University Tianjin 300387 China Laboratory for Quantum Design of Functional Materials School of Physics and Electronic Engineering Jiangsu Normal University Xuzhou 221116 China Skolkovo Institute of Science and Technology Skolkovo Innovation Center 3 Nobel St. Moscow 121205 Russia Moscow Institute of Physics and Technology 9 Institutskiy Lane Dolgoprudny city Moscow Region 141700 Russia International Center for Materials Discovery Northwestern Polytechnical University Xi'an 710072 China Center for High Pressure Science and Technology Advanced Research Beijing 100193 China Center for High Pressure Science State Key Laboratory of Metastable Materials Science and Technology School of Science Yanshan University Qinhuangdao 066004 China National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China

We study the stability of Li-O compounds as a function of pressure, with rich phase diagram, diverse properties, and fundamental chemical interest in mind. Using the ab initio evolutionary algorithm USPEX, we predict the stability of compounds LiO4, Li5O3, and Li6O under pressure. Unexpectedly, LiO2 will decompose to Li2O2+LiO4 in the pressure range 6–18 GPa. LiO4, formed at the pressure of just 6 GPa, can be seen as ɛ−O8 accepting two electrons from two Li atoms. This phase is superconducting, with Tc up to 12.2 K at 10 GPa. This is remarkable, because elemental oxygen becomes superconducting at much higher pressure (96 GPa) and has much lower Tc (<0.6 K), and suggests that chemical alloying with other elements has the potential of not only decreasing metallization pressure, but also of increasing Tc. Since ɛ−O8 is called red oxygen, LiO4 can be identified as “lithium red-oxide”, and is distinct from superoxide. Additionally, Li5O3 is stable at pressures above 70 GPa and can be represented as a hybrid structure 4Li2O·Li2O2, and electride suboxide Li6O is stable above 62 GPa.

关键词： Chemical Physics & Physical Chemistry Pressure effects Structural properties Oxides Superconductors Density functional calculations Pressure techniques

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Energy, phonon, and dynamic stability criteria of 2d materials

arXiv

引用

arXiv 2019年

作者： Malyi, Oleksandr I. Sopiha, Kostiantyn V. Persson, Clas Centre for Materials Science and Nanotechnology Department of Physics University of Oslo P.O. Box 1048 Blindern OsloNO-0316 Norway Ångström Solar Center Solid State Electronics Department of Engineering Sciences Uppsala University Box 534 UppsalaSE-75121 Sweden

First-principles calculations have become a powerful tool to exclude the Edisonian approach in search of novel 2d materials. However, no universal first-principles criteria to examine the realizability of hypothetical 2d materials have been established in the literature yet. Because of this, and since the calculations are always performed in an artificial simulation environment, one can unintentionally study compounds that do not exist in the experiments. Although investigations of physics and chemistry of unrealizable materials can provide some fundamental knowledge, the discussion of their applications can mislead experimentalists for years and increase the gap between experimental and theoretical research. By analyzing energy convex hull, phonon spectra, and structure evolution during ab initio molecular dynamics simulations for a range of synthesized and recently proposed 2d materials, we construct energy, phonon, and dynamic stability filters which need to be satisfied before proposing novel 2d compounds. We demonstrate the power of the suggested filters for several selected 2d systems, revealing that some of them cannot be ever realized experimentally. Copyright © 2019, The Authors. All rights reserved.

关键词： Phonons

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Observation of Fano resonance in photoluminescence of a two-dimensional magnetic semiconductor

arXiv

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arXiv 2019年

作者： Gu, Pingfan Tan, Qinghai Wan, Yi Li, Ziling Peng, Yuxuan Lai, Jiawei Ma, Junchao Yao, Xiaohan Yuan, Kai Sun, Dong Peng, Bo Zhang, Jun Ye, Yu State Key Laboratory for Artificial Microstructure & Mesoscopic Physics Nanooptoelectronics Frontier Center of the Ministry of Education School of Physics Peking University Beijing100871 China State Key Laboratory of Superlattices and Microstructures Institute of Semiconductors & Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing100049 China International Center of Quantum Matter Beijing100871 China Collaborative Innovation Center of Quantum Matter Beijing100871 China National Engineering Research Center of Electromagnetic Radiation Control Materials State Key Laboratory of Electronic Thin Films and Integrated Devices School of Microelectronics and Solid State Electronics University of Electronic Science and Technology of China Chengdu610054 China Beiing Academy of Quantum Information Science Beijing100193 China

Quantum interference gives rise to the asymmetric Fano resonance line shape when the final states of an electronic transition follows within a continuum of states and a discrete state, which has significant applications in optical switching and sensing. The resonant optical phenomena associated with Fano resonance have been observed by absorption spectra, Raman spectra, transmission spectra, etc., but have rarely been reported in photoluminescence (PL) spectroscopy. In this work, we performed spectroscopic studies on layered chromium thiophosphate (CrPS4), a promising ternary antiferromagnetic semiconductor with PL in near-infrared wavelength region and observed Fano resonance when CrPS4 experiences phase transition into the antiferromagnetic state below Néel temperature (38 K). The photoluminescence of the continuum states results from the d band transitions localized at Cr3+ ions, while the discrete state reaches saturation at high excitation power and can be enhanced by the external magnetic field, suggesting it is formed by an impurity level from extra atomic phosphorus. Our findings provide insights into the electronic transitions of CrPS4 and their connection to its intrinsic magnetic properties. Copyright © 2019, The Authors. All rights reserved.

关键词： Chromium compounds

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