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Exploitable magnetic anisotropy and half-metallicity controls in multiferroic van der Waals heterostructure

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npj Computational Materials 2023年第1期9卷 60-70页

作者： Yaping Wang Xinguang Xu Weixiao Ji Shengshi li yanlu li Xian Zhao State Key Lab of Crystal Materials and Institute of Crystal Materials Shandong UniversityJinan 250100China Spintronics Institute University of JinanJinan 250022China Center for Optics Research and Engineering of Shandong University Shandong UniversityQingdao 266237China

Two-dimensional(2D)XY ferromagnets have drawn pronounced interest in recent years,but the characteristic of easy-plane magnetization restricts their application in spintronics to some ***,we propose a general strategy for constructing multiferroic van der Waals heterostructures,aiming to achieve electrical control over the magnetic anisotropy in 2D XY *** validity of this strategy is verified by the heterostructure composed of ferromagnetic VBi_(2)Te_(4) and ferroelectric In_(2)Se_(3) *** manipulating the polarized states of In_(2)Se_(3),the VBi_(2)Te_(4) can be reversibly transformed between 2D XY and Heisenberg ferromagnets,characterized by the switching of easy magnetization axis between in-plane and out-of-plane *** interestingly,accompanied by the changes in magnetic anisotropy,the VBi_(2)Te_(4) also demonstrates a phase transition from a semiconductor to a half-metal state,which can be ascribed to the band alignment and interfacial charge *** switchable magnetic and electronic properties enable the heterostructure to be utilized in nonvolatile memory and logic ***,the half-metallicity and magnetocrystalline anisotropy energy of the heterostructure can be effectively tuned by biaxial *** findings not only pave the way for electrically nonvolatile control of 2D XY ferromagnet,but also facilitate the development of interfacial magnetoelectric physics and applications.

关键词： anisotropy metallic magnetic

Improved Na storage and Coulombic efficiency in TiP_(2)O_(7)@C microflowers for sodium ion batteries

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Nano Research 2021年第1期14卷 139-147页

作者： Jun Pan Nana Wang lili li Feng Zhang Zhenjie Cheng yanlu li Jian Yang Yitai Qian Key Laboratory of Colloid and Interface Chemistry Ministry of EducationSchool of Chemistry and Chemical EngineeringShandong UniversityJinan 250100China Shenzhen Research Institute of Shandong University Shenzhen 518000China Institute for Superconducting and Electronic Materials Australian Institute for Innovative MaterialsUniversity of Wollongong Innovation CampusNorth Wollongong New South Wales 2500Australia State Key Lab of Crystal Materials Shandong UniversityJinan 250100China

Ti-based anode materials in sodium ion batteries have attracted extensive interests due to its abundant resources,low toxicity,easy synthesis and long cycle ***,low Coulombic efficiency and limited specific capacity affect their ***,cubic-phase TiP_(2)O_(7)is examined as anode materials,using in-situ/ex-situ characterization *** is concluded that the redox reactions of Ti4^(+)/Ti^(3+)and Ti^(3+)/Ti^(0)consecutively occur during the discharge/charge processes,both of which are highly *** reactions make the specific capacity of TiP_(2)O_(7)even higher than the case of TiO2 that only contains a simple anion,0^(2-).Interestingly,Ti species participate only one of the redox reactions,due to the remarkable difference in local structures related to the sodiation *** stable discharge/charge products in TiP_(2)O_(7)reduce the side reactions and improve the Coulombic efficiency as compared to T *** features make it a promising Ti-based anode for sodium ion ***,TiP_(2)O_(7)@C microflowers exhibit excellent electrochemical performances,〜109 mAh·g^(-1)after 10,000 cycles at 2 A·g^(-1),or 95.2 mAh·g^(-1)at 10 A·g^(-1).The results demonstrate new opportunities for advanced Ti-based anodes in sodium ion batteries.

关键词： TiP_(2)O_(7) electrochemical reactions anodes sodium ion batteries

Abnormal lattice occupation of Mo and related polarons in liNbO_(3): Hybrid density functional theory investigation

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Journal of Materiomics 2020年第1期6卷 183-191页

作者： lili li yanlu li Xian Zhao Xiufeng Cheng Yongjun Fan Institute of Crystal Matierials and State Key Laboratory of Crystal Materials Shandong UniversityJinanShandong250100China Center for Optics Research and Engineering of Shandong University Shandong UniversityJinanShandong250100China

Studies have reported that Mo-doped liNbO_(3) exhibits excellent photorefractive performance,which may be attributed to the Mo abnormally occupation in Nb sites(MoNb)and the MoNb photorefractive ***,we investigate the basic characteristics of Mo-doped liNbO_(3),including the preferable substitutional sites,doping stability,lattice relaxation,and electronic structures using the spin-polarised density functional theory within semi-local and hybrid ***,the type and properties of the polarons in Mo-doped liNbO_(3) are studied intensively,and the advantages of MoNb polarons with respect to the Moli polarons are *** calculation results of both transfer energies and defect formation energies show that MoNb are preferable to be formed in both stoichiometric and congruent liNbO_(3),while Mo substitutional li(Moli)is consumed in small *** could act as small bound polarons that exhibit fast response to light with respect to the Moli bound *** introduced double-centre by Mo doping is partly responsible for the excellent photorefractive properties of Mo-doped liNbO_(3).

关键词： Density functional theory Electronic property Polaron Mo-doped liNbO_(3)

Switchable half-metallicity in A-type antiferromagnetic NiI_(2)bilayer coupled with ferroelectric In_(2)Se_(3)

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npj Computational Materials 2022年第1期8卷 2091-2098页

作者： Yaping Wang Xinguang Xu Xian Zhao Weixiao Ji Qiang Cao Shengshi li yanlu li State Key Lab of Crystal Materials and Institute of Crystal Materials Shandong University250100JinanChina Center for Optics Research and Engineering of Shandong University Shandong University266237QingdaoChina Spintronics Institute University of Jinan250022JinanChina

Electrically controlled half-metallicity in antiferromagnets is of great significance for both fundamental research and practical ***,by constructing van der Waals heterostructures composed of two-dimensional(2D)A-type antiferromagnetic NiI_(2)bilayer(bi-NiI_(2))and ferroelectric In_(2)Se_(3)with different thickness,we propose that the half-metallicity is realizable and switchable in the bi-NiI_(2)proximate to In_(2)Se_(3)bilayer(bi-In_(2)Se_(3)).The polarization flipping of the bi-In_(2)Se_(3)successfully drives transition between half-metal and semiconductor for the bi-NiI_(2).This intriguing phenomenon is attributed to the joint effect of polarization field-induced energy band shift and interfacial charge ***,the easy magnetization axis of the bi-NiI_(2)is also dependent on the polarization direction of the bi-In_(2)Se_(3).The half-metallicity and magnetic anisotropy energy of the bi-NiI_(2)in heterostructure can be effectively manipulated by *** findings provide not only a feasible strategy to achieve and control half-metallicity in 2D antiferromagnets,but also a promising candidate to design advanced nanodevices.

关键词： polarization metallic ferroelectric

Electrical properties of yttrium calcium oxyborate crystal annealed at high temperature and low oxygen partial pressure

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Journal of Materiomics 2019年第3期5卷 363-371页

作者： Shiwei Tian lili li Feifei Chen Chao Jiang Fapeng Yu yanlu li Xiulan Duan Zhengping Wang Shujun Zhang Xian Zhao State Key Laboratory of Crystal Materials Advanced Research Center for Optics of Shandong UniversityJinan250100China ISEM Australia Institute of Innovative MaterialsUniversity of WollongongWollongongNSW2500Australia

The yttrium calcium oxyborate crystal(YCa_(4)O(BO_(3))_(3),YCOB)has been actively studied for hightemperature piezoelectric sensing *** this work,the stability of electric properties of YCOB crystal annealed in critical conditions(high-temperatures of 900-1100℃ with a low oxygen partial pressure of 4×10^(-6) atm for 24 h)was investigated and the recovery mechanism for the electrical resisitivity,dielectric permittivity and dielectric loss were studied,taking advantage of the X-ray photoelectron spectra and the first principle *** electrical resistivity of the annealed YCOB crystal was slightly decreased when compared to the pristine counterpart,being(2-5)×10^(7) Ω·cm at 850*** dielectric permittivity and dielectric loss were found to increase after annealing,showing recoverable behaviours after thermal treatment above 650℃ in *** calculated vacancy formation energy indicates that the oxygen vacancy is the dominant defects in *** formation of oxygen vacancy weakens the chemical bonding strength between B(Ca or Y)and O atoms,introduces extra donor levels in the band gap,which excites the electrons to conduction band more easily thus enhances the electrical conductivity and dielectric *** recovered electrical properties are believed to be associated with the reduced vacancy defects at elevated temperatures in air.

关键词： YCOB crystal Recoverable dielectric properties First principle calculations

Pseudocapacitance boosted N-doped carbon coated Fe7S8 nanoaggregates as promising anode materials for lithium and sodium storage

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Nano Research 2020年第3期13卷 691-700页

作者： Yanli Zhou Ming Zhang Qi Wang Jian Yang Xingyun Luo yanlu li Rong Du Xinsheng Yan Xueqin Sun Caifu Dong Xiaoyu Zhang Fuyi Jiang School of Environmental and Material Engineering Yantai University Yantai 264005China Key Laboratory of Colloid and Interface Chemistry Ministry of Education School of Chemistry and Chemical EngineeringShandong UniversityJinan 250100China Institute cf Crystal Materials and State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100China

Herein,the core-shell structured N-doped carbon coated Fe7S8 nano-aggregates(Fe7S8@NC)were controllably prepared via a simple three-step synthesis *** appropriate thickness of N-doped carbon layer outside Fe7S8 nano-aggregates can not only inhibit the particle pulverization induced by the big volume changes of Fe7S8,but can increase the electron transfer *** hierarchical Fe7S8 nano-aggregates composed of some primary nanoparticles can accelerate the lithium or sodium diffusion *** anode materials for li-ion batteries(liBs),the well-designed Fe7S8@NC nanocomposites exhibit outstanding lithium storage performance,which is better than that of pure Fe7S8,Fe3O4@NC and Fe7S8@*** these nanocomposites,the N-doped carbon coated Fe7S8 with carbon content of 26.87 wt.%shows a high reversible specific capacity of 833 mAh·g^−1 after 1,000 cycles at a high current density of 2 A·g^−*** above electrode also shows excellent high rate sodium storage *** experimental and theoretical analyses indicate that the outstanding electrochemical performance could be attributed to the synergistic effect of hierarchical Fe7S8 nanostructure and conductive N-doped carbon *** quantitative kinetic analysis indicates that the charge storage of Fe7S8@NC electrode is a combination of diffusion-controlled battery behavior and surface-induced capacitance behavior.

关键词： FeyS8 N-doped carbon anode materials li-ion batteries Na-ion batteries

Nickel effects on growth and antioxidative enzymes activities in desert plant Zygophyllum xanthoxylon (Bunge) Maxim

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Research in Cold and Arid Regions 2010年第5期2卷 436-444页

作者： yanlu XinRong li MingZhu He ZhengNing Wang HuiJuan Tan Shapotou Desert Research and Experiment Station Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou Gansu 730000 China

One-month old Zygophyllum xanthoxylon seedlings were grown under five different Ni concentrations （0, 50, 150, 450 and 900 mg/kg）. Growth parameters, tissues Ni accumulation, soluble protein content, photosynthetic pigment content, lipid peroxidation, antioxidative enzyme activities, and proline content were studied after one month of Ni exposure. The significant reduction in fresh biomass in the shoot and roots was detected at high Ni concentrations （≥450 mg/kg）, whereas dry biomass was not significantly affected in both organs by any of the Ni doses tested. The Ni contents in the shoots and roots increased in a dose-dependent manner, and Ni contents in roots were higher than that in shoots at all treatments. The high Ni doses elevated soluble protein contents in leaves and roots. No visible symptoms of chlorosis were observed in leaves of plants grown in presence of Ni. Malondialdehyde （MDA） contents significantly increased in leaves and roots at high Ni treatments （≥450 mg/kg）, indicating that Ni induces oxidative stress. Enzyme activities might play a central role in cellular protection against the Ni induced oxidative stress. Proline contents proportionally increased with the elevated Ni concentrations. Zygophyllum xanthoxylon revealed moderate Ni tolerance under tested culture conditions, and could be used as tools for revegetation for erosion control in moderate Ni contaminated sites.

关键词： Zygophyllum xanthoxylon Ni photosynthetic pigment malondialdehyde proline

大规模远程学习是教育的未来吗——基于国际组织的调查

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上海教育科研 2023年第2期 77-83页

作者：李艳璐上海市杨浦区教育学院 200092

信息技术的突飞猛进使人们对远程学习充满信心,造成了学生学习似乎可以脱离学校教育的幻象。疫情期间,远程学习成为主要方式,在线平台占据优先地位,改变了教师工作状况和学生评价体系,这给了人们评估大规模远程学习效果的机会。国际组... 详细信息

信息技术的突飞猛进使人们对远程学习充满信心,造成了学生学习似乎可以脱离学校教育的幻象。疫情期间,远程学习成为主要方式,在线平台占据优先地位,改变了教师工作状况和学生评价体系,这给了人们评估大规模远程学习效果的机会。国际组织调查表明,远程学习造成了学习悖论,产生了学习损失、学习机会不公和社会情感问题。这皆因基础设施、家庭环境、课程体系及教师信息技术素养等外部支撑条件尚不充分,以及远程学习本身在教育性、学生自我认知及师生互动成效方面也存在若干固有不足。因此,大规模远程学习不是未来,构建以学校为中心的混合学习环境才是前进的方向。

关键词：疫情远程学习反思国际组织调查

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磷酸二氢钾晶体表面点缺陷的理论研究

硅酸盐学报 2023年第6期51卷 1412-1424页

作者：赵骁骥李妍璐赵显山东大学晶体材料研究院晶体材料国家重点实验室济南250100 山东大学光学高等研究中心山东青岛266237

磷酸二氢钾(KH_(2)PO_(4),KDP)晶体是目前唯一可在惯性约束核聚变装置中得到实际应用的非线性光学材料。由于晶体缺陷大大降低了非线性光吸收、激光损伤阈值等光学性能,因此,探明KDP晶体缺陷对其电子结构和光学性质的影响机制对于提升... 详细信息

磷酸二氢钾(KH_(2)PO_(4),KDP)晶体是目前唯一可在惯性约束核聚变装置中得到实际应用的非线性光学材料。由于晶体缺陷大大降低了非线性光吸收、激光损伤阈值等光学性能,因此,探明KDP晶体缺陷对其电子结构和光学性质的影响机制对于提升其光学性能具有重要意义。本工作采用第一性原理方法计算了KDP晶体(100)和(101)表面上氢空位和氧空位缺陷的结构、稳定性及电子结构特征,研究了酸环境对表面空位缺陷结构及电子结构的影响规律及微观机制。结果表明:氢空位和氧空位缺陷在KDP晶体(100)和(101)表面上均比在晶体中更容易形成。(100)表面对氢空位及氧空位均具有较高的容忍性,然而,(101)表面的氧空位极易失去电子,在带隙中引入缺陷能级,从而引起额外光吸收,对晶体光学性质产生不利影响。酸性环境会导致(100)表面产生更多氧空位,并诱导产生氧空位缺陷能级;同时,酸性环境有利于修复表面氢空位,并消除氧空位在(101)表面电子结构中引入的缺陷态,有利于提升晶体(101)表面质量及光学质量。

关键词：第一性原理磷酸二氢钾表面缺陷