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Edge-Dependent Electronic and Magnetic Characteristics of Freestanding β_(12)-Borophene Nanoribbons

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Nano-Micro Letters 2018年第1期10卷 124-136页

作者： Sahar Izadi Vishkayi Meysam Bagheri Tagani Department of Physics Computational Nanophysics Laboratory (CNL) University of Guilan

This work presents an investigation of nanoribbons cut from β_(12)-borophene sheets by applying the density functional theory. In particular, the electronic and magnetic properties of borophene nanoribbons(BNR) are studied. It is found that all the ribbons considered in this work behave as metals, which is in good agreement with the recent experimental results. β_(12)-BNR has significant diversity due to the existence of five boron atoms in a unit cell of the sheet. The magnetic properties of the ribbons are strongly dependent on the cutting direction and edge profile. It is interesting that a ribbon with a specific width can behave as a normal or a ferromagnetic metal with magnetization at just one edge or two edges. Spin anisotropy is observed in some ribbons, and the magnetic moment is not found to be the same in both edges in an antiferromagnetic configuration. This effect stems from the edge asymmetry of the ribbons and results in the breaking of spin degeneracy in the band structure. Our findings show that β_(12) BNRs are potential candidates for next-generation spintronic devices.

关键词： Borophene nanoribbons Electronic and magnetic properties Density functional theory

Curvature and Zeeman effects on persistent currents in a multi-walled carbon nanotorus

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Chinese Physics B 2010年第1期19卷 403-408页

作者：徐宁丁建文马明明汤贤 Department of Physics and Institute for nanophysics and Rare-earth Luminescence Xiangtan University

Taking into account both the intrinsic curvature and Zeeman effects, persistent currents in a multi-walled carbon nanotorus are explored by using a supercell method, within the tight-binding formalism. It is shown that in the absence of the Zeeman effect, the intrinsic curvature induces some dramatic changes in energy spectra and thus changes in the shape of the flux-dependent current. A paramagnetism-diamagnetism transition is observed. With consideration of the Zeeman splitting energy, the period of persistent current is destroyed, and a diamagnetism-paramagnetism transition is obtained at high magnetic field. In addition, we further explore the effect of external electric field energy (Eef) on persistent current, indicating that it changes unmonotonously with Eef.

关键词： multi-walled carbon nanotorus tight-binding model persistent current

Persistent currents in three-dimensional shell-doped nanorings

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Chinese Physics B 2009年第5期18卷 2030-2034页

作者：徐宁丁建文陈宏波马明明 Department of Physics & Institute for nanophysics and Rare-earth Luminescence Xiangtan University

The persistent current in three-dimensional （P × N2） nanorings as a function of the unit cell number （P）, the channel number （M =N2）, surface disorder （ζ）, and temperature （T） is theoretically investigated in terms of rotational symmetry. On the whole, the typical current increases linearly with √M but decreases exponentially with P, while wide fluctuations exist therein. In the presence of surface disorder, the persistent current decreases with ζ in the regime of weak disorder but increases in the regime of strong disorder. In addition, it is found that the persistent current in perfect rings decreases exponentially with temperature even at T 〈 T＊, while in most disorder rings, the typical current decreases slightly with temperature at T 〈 T＊.

关键词： three-dimensional nanorings tight-binding model persistent current

Curvature and Hybridization Effects on the Persistent Current of a Carbon Nanotorus

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Chinese Physics Letters 2009年第7期26卷 218-221页

作者：徐宁丁建文陈宏波马明明 Department of Physics and Institute for nanophysics and Rare-earth Luminescence Xiangtan University Xiangtan 411105

To accurately describe the persistent current for various toroidad carbon nanotubes （TCNs）, a semiempirical sp3 tight-binding model is presented, in which the intrinsic curvature and hybridization have been fully taken into account. The calculations show that the curvature and hybridization can induce dramatic changes in the energy spectra of TCNs such as the Fermi energy EF shifting up, an energy gap opening at IF, F, and the energy spectrum symmetry about EF destroyed, which leads to a decrease of persistent current and changes in the shape Of the flux-dependent current. In the presence of curvature and hybridization, the persistent current in non-armchair TCNs is nearly an order of magnitude lower than that obtained by using the Brillouin-zone folding approach, while it is of the same order of magnitude in armchair TCNs.

关键词： ELECTRONIC-PROPERTIES RING TRANSISTOR NANOTUBES TRANSPORT TORI

Photochromic effect of HoPO_4:Li^+ powder

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Chinese Optics Letters 2015年第3期13卷 59-62页

作者：文晴肖思国高学军夏文斌阳效良 Faculty of Physics and Optoelectronic Engineering Institute for Nanophysics and Rare-Earth LuminescenceXiangtan University

Li^＋-doped HoPO4 powders with a pure tetragonal phase are successfully synthesized by the co-precipitation method. It exhibits an obvious color change under sunlight and tri-phosphor fluorescent light illumination. The introduction of Li^＋ ions into HoPO4 can further enhance its photochromic property effectively. The doped Li^＋ ions induce changes in the crystal structure. The spectral characteristics and thus photochromic properties of HoPO4 are explored. The improved HoPO4 powder, when used as a photochromic material, has wide-ranging prospects in security, decoration, and other applications.

关键词： Ho powder

Experimental investigation of a novel junction-modulated hetero-layer tunnel FET with the striped gate for low power applications

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Science China(Information Sciences) 2023年第6期66卷 313-314页

作者： Zhongxin LIANG Yang ZHAO Kaifeng WANG Jieyin ZHANG Jianjun ZHANG Ming LI Ru HUANG Qianqian HUANG Key Laboratory of Microelectronics Devices and Circuits (MOE) School of Integrated CircuitsPeking University Key Laboratory of nanophysics and Devices Institute of PhysicsChinese Academy of Sciences Beijing Advanced Innovation Center for Integrated Circuits

Silicon-based tunneling field effect transistor(TFET) with a band-to-band tunneling mechanism has been widely studied due to its ultra-steep subthreshold swing(SS),ultralow leakage current(Ioff),and good complementary... 详细信息

关键词： FIELD-EFFECT TRANSISTORS

Reproduced Giant Localization Length of Two-Side Surface Disordered Nanowires with Long-Range Correlation

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Chinese Physics Letters 2011年第10期28卷 184-187页

作者：赵为丁建文 Department of Physics&Institute for nanophysics and Rare-earth Luminescence Xiangtan UniversityXiangtan 411105

We numerically investigate the normalized localization length of two-side rough nanowires as functions of energy,magnetic field and correlation strength by using modular recursive Green's function method.It is found that in the absence of correlation,while in the presence of magnetic field,the localization length increases linearly for two-side roughness,which is different to diverging exponentially for one-side roughness.Moreover,the localization of electrons is suppressed in the low energy region,but enhanced in the high energy region.In the presence of correlation,especially,an exponential enhancement in the localization length resumes in high energy region,in contrast to that in low energy region,the long-range correlations abnormally enhance the localization of electrons.A competitive mechanism is proposed to explain this behavior.

关键词： nanowires roughness resume

Quenched Fe moment in the collapsed tetragonal phase of Ca_(1-x)Pr_x Fe_2As_2

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Chinese Physics B 2013年第5期22卷 55-59页

作者：马龙吉高峰代佳 Saha S R Drye T Paglione J 于伟强 Department of Physics Renmin University of China Center for nanophysics and Advanced Materials Department of PhysicsUniversity of MarylandCollege Park

We report 7SAs NMR studies on single crystals of rare-earth doped iron pnictide superconductor Ca1-xPrxFe2As2. In both cases of x = 0.075, 0.15, a large increase of Vq upon cooling is consistent with the tetragonal-collapsed tetragonal structure transition. A sharp drop of the Knight shift is also seen just below the structure transition, which suggests the quenching of Fe local magnetism, and therefore offers important understanding of the collapsed tetragonal phase. At even low temperatures, the 1/75 T1 is enhanced and forms a peak at T ≈ 25 K, which may be caused by the magnetic ordering of the Pr3＋ moments or soin dynamics of mobile domain walls.

关键词： quenched Fe moment collapsed tetragonal phase iron pnictides nuclear magnetic resonance

Massless and Massive Particle-in-a-Box States in Single- and Bi-Layer Graphene

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Nano Research 2011年第4期4卷 385-392页

作者： Sungjae Cho Michael Fuhrer Department of Physics and Center for nanophysics and Advanced Materials University of Maryland College Park Maryland 20742 USA

通过短、阶段协调的 metal-graphene-metal 设备的电子运输通过 atomically 锋利的金属领先定义的 particle-in-a-box-like 状态经由反响的传播发生。我们学习 particle-in-a-box 状态的光谱为单个层并且双性人层 graphene，相应于无团... 详细信息

通过短、阶段协调的 metal-graphene-metal 设备的电子运输通过 atomically 锋利的金属领先定义的 particle-in-a-box-like 状态经由反响的传播发生。我们学习 particle-in-a-box 状态的光谱为单个层并且双性人层 graphene，相应于无团、巨大二维(2-D ) 费米子。粒子数字 n 的功能为巨大的 2-D 费米子(在双性人层 graphene 的电子) 为无团的 2-D 费米子(在单个层的 graphene 的电子) 和 D (n) 常数显示出期望的关系 D (n) n 1/2 的状态 D 的密度。无团、巨大的分散关系的单个参数被发现，也就是费密速度 F = 1.1 浲瑡潩 ? 景挠癯污湥 ? 潢摮 ? 敢睴敥 ? 桴 ? 桰湥汹猠'T 瑳瑩敵瑮 ? 景琠敨瀠牯桰特湩。

关键词：石墨粒子质量电子传输粒子数密度费米子金属导线金属器件金属石墨