Magnetic structure and magnetic transport properties of armchair arsenene nanoribbons
作者：
Sheng, R. Q.;Sun, L.;Deng, X. Q.* ;Fan, Z. Q.;Zhang, Z. H.
期刊：
Solid State Communications ,2019年297:27-33 ISSN：0038-1098
通讯作者：
Deng, X. Q.
作者机构：
[Sheng, R. Q.; Fan, Z. Q.; Zhang, Z. H.; Sun, L.; Deng, X. Q.] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Deng, X. Q.] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
关键词：
Semiconductors;Magnetism;Spin-filtering;First-principles calculation
摘要：
Inducing magnetism for arsenene is important for developing high-performance spintronic devices. Here, we investigate the electronic and magnetic properties of armchair arsenene nanoribbons doped with transition metal Mn atom by the ab initio electronic structure calculations and quantum transport simulations. It is found that such structures are stable by calculated formation energy and molecular dynamics simulation. Magnetic states can be obtained by doping Mn atom in such ribbons at different doping-positions with the distance from the Mn atom to the ribbon edges. AAsNR-Mn experiences a transition from a half-semiconductor to a half-metal by applying an external electric field. Moreover, it possesses an outstanding magnetic device nature, such as perfect spin filtering effect (100%), and a spin-valve feature with giant magnetoresistance (GMR)approaching 106%. Our calculation indicates AAsNRs-Mn has a promising application for multifunctional spintronic devices. © 2019 Elsevier Ltd
语种：
英文
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Spin transport investigation of two type silicene nanoribbons heterostructure
作者：
Deng, X. Q.* ;Sheng, R. Q.
期刊：
Physics Letters A ,2019年383(1):47-53 ISSN：0375-9601
通讯作者：
Deng, X. Q.
作者机构：
[Sheng, R. Q.; Deng, X. Q.] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Deng, X. Q.] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
关键词：
Heterostructure;Silicene nanoribbons (ZSiNRs);Spin-filtering
摘要：
Based on first principles calculation method, we design and investigate the spin transport properties of two type heterostructures based on zigzag silicene nanoribbons (ZSiNRs). The first one consists of hydrogen-terminated ZSiNR (ZSiNR-H) and Rx-terminated ZSiNR (ZSiNR-Rx), here, Rx = O, S, P. The rectification behavior can be observed for heterostructures consisting of ZSINR-H and ZSiNR-O (ZSiNR-S). The second one can be fabricated with a ZSiNR-Rx central scatter region between two ZSiNR-H electrodes. The results show that this device could maintain its good spin filtering effect for ZSiNR-O model in parallel (P) and antiparallel (AP) spin configuration with large bias range. Then we further investigate the spin-dependent transport with various length of ZSiNR-O region, and find that better spin filtering effect (near 100% spin polarization) can be observed for longer ZSiNR-O region. ZSiNR-S model show analogous spin filtering effect. However, neither rectification behavior nor spin filtering effect arise for ZSiNR-P models. (C) 2018 Published by Elsevier B.V.
语种：
英文
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Electronic and thermal spin effect of molecular nanowires between graphene electrodes
作者：
Deng, X. Q.;Sheng, R. Q.
期刊：
RSC Advances ,2018年8(60):34182-34191 ISSN：2046-2069
通讯作者：
Deng, XQ
作者机构：
[Deng, X. Q.; Sheng, R. Q.] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Deng, XQ ] ;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
摘要：
Based on the first-principles method, the electronic spin transport properties of terphenyl molecule bridging in zigzag graphene nanoribbon (ZGNR) electrodes with three connecting linkages were investigated, including dangling, heptagon, and pentagon-linkages. For the pentagon-linkage system, we observed a perfect spin filtering effect in the parallel (P) configuration (at almost 100% spin polarization), with the heptagon-linkages system following next (85-95% spin polarization), however, the spin filtering effect is almost negligible for the dangling-linkages system. In the antiparallel (AP) configuration, the pentagon- and heptagon-linkage systems also showed a high spin filtering effect. The terphenyl molecule was then replaced by carbon chains based on the pentagon-linkages, and these devices also show a perfect spin filtering effect (100% spin polarization). Finally, the thermally induced spin transport for the carbon chains model with pentagon-linkages was explored, and this system exhibits almost 100% thermal spin polarization. © The Royal Society of Chemistry.
语种：
英文
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Experimental and CFD investigation on temperature distribution of a serpentine tube type photovoltaic/thermal collector
作者：
Zhou, Jicheng* ;Ke, Haoyun;Deng, Xiaoqing
期刊：
Taiyo Enerugi ,2018年174:735-742 ISSN：0038-092X
通讯作者：
Zhou, Jicheng
作者机构：
[Ke, Haoyun; Zhou, Jicheng] Cent S Univ, Sch Energy Sci & Engn, Changsha 410083, Hunan, Peoples R China.;[Deng, Xiaoqing] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Zhou, Jicheng] C;Cent S Univ, Sch Energy Sci & Engn, Changsha 410083, Hunan, Peoples R China.
关键词：
Computational fluid dynamics;Photovoltaic/thermal collector;Serpentine tube;Temperature distribution
摘要：
The issue of temperature distribution is significant in the research of PV/T collectors due to the inherent negative temperature characteristics of solar cells. In this paper, a three-dimensional thermal model of a water-cooled flat-panel PV/T collector with serpentine tube is established using the finite element method, which the simulation accuracy is verified by the experimental data. We investigate the effect of multiple factors on the temperature distribution, including tube spacing, absorber materials, inlet velocity and tube row arrangement, respectively. Our results show that reducing tube spacing is the most effective way to increase uniformity of temperature distribution, and using absorber materials with better thermal properties can improve the temperature distribution partly. However, increasing the fluid inlet velocity has little effect on establishing a uniform temperature field though it can reduce the plate temperature. Temperature is hardly affected by the tube row arrangement, and uniform temperature field cannot be obtained with more bends.
语种：
英文
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利用网络教学平台将物理实验带入理论课堂
作者：
范志强;彭金池;唐贵平;邓敏;邓小清
期刊：
高教学刊 ,2017年(9):56-57 ISSN：2096-000X
作者机构：
长沙理工大学 物理与电子科学学院,湖南 长沙,410114;[邓敏; 唐贵平; 彭金池; 邓小清; 范志强] 长沙理工大学
关键词：
大学物理;网络教学平台;教学模式
摘要：
文章对目前大学物理课程与大学物理实验课程脱节的现状进行了阐述与分析,提出了利用网络教学平台将大学物理实验带入理论课堂的新教学模式,并对大学物理的教学方法和考核方式进行了探索与实践。
语种：
中文
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Modulation of the magnetic properties in zigzag-edge graphene nanoribbons by connection sites
作者：
Deng, X. Q.* ;Zhang, Z. H.* ;Sun, L.;Wu, L. J.
期刊：
Organic Electronics ,2017年41:376-383 ISSN：1566-1199
通讯作者：
Deng, X. Q.;Zhang, Z. H.
作者机构：
[Deng, X. Q.; Zhang, Z. H.; Sun, L.; Wu, L. J.] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Deng, XQ; Zhang, ZH] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
关键词：
Antiferromagnetism;Electrodes;Energy gap;Ferromagnetic materials;Ferromagnetism;Graphene;Ground state;Magnetic properties;Nanoribbons;Antiferromagnetic ground state;Antiferromagnetic state;Ferromagnetic state;First principles method;Graphene nano-ribbon;Graphene nanoribbons;Semiconductor behavior;Spin configurations;Semiconductor junctions
摘要：
Based on the first-principles method, the magnetic properties for zigzag–edge graphene nanoribbon (ZGNR) junctions are investigated. The results show the system had the ferromagnetic or antiferromagnetic ground state depending on the connection sites between ZGNR electrodes and the central ZGNR. The junction displays a metallic behavior when the central ZGNR is connected at the middle site of electrodes with a ferromagnetic state, but shows obvious spin semiconductor feature when the connection site is shifted to the edge of the ZGNR. For the antiferromagnetic states, all models show a semiconductor behavior, which originates from the spin-degenerate edge states. While for the antiparallel spin configuration, the spin density of the central ribbon is affected by connection sites, and it shows weaker little by little with the central ribbon moving from bottom to the middle site, which is different obviously from ferromagnetic or antiferromagnetic state. When one edge state of the central ZGNR is broken, bipolar spin semiconductor features can be obtained with different band gaps at suitable connection sites. © 2016 Elsevier B.V.
语种：
英文
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Symmetry-dependent spin transport properties of a single phenalenyl or pyrene molecular device
作者：
Fan, Zhi-Qiang* ;Sun, Wei-Yu;Zhang, Zhen-Hua* ;Deng, Xiao-Qing;Tang, Gui-Ping;...
期刊：
Carbon ,2017年122:687-693 ISSN：0008-6223
通讯作者：
Fan, Zhi-Qiang;Zhang, Zhen-Hua
作者机构：
[Sun, Wei-Yu; Deng, Xiao-Qing; Tang, Gui-Ping; Zhang, Zhen-Hua; Fan, Zhi-Qiang; Xie, Hai-Qing] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Fan, ZQ; Zhang, ZH] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
摘要：
Spintronic systems exploit the fact that the electron current is composed of spin-up and spin-down carriers, which are more easily disturbed than electronic systems. Here, we investigate the spin transport properties of a single phenalenyl or pyrene molecule connected to zigzag graphene nanoribbon electrodes by using the non-equilibrium Green's function formalism with density functional theory. We found the difference of the symmetry on these two molecules will bring a remarkable effect on the spin transport properties of the devices. The spin-resolved currents of the single pyrene molecular device are much lower than that of the single phenalenyl molecular device when they all connected to electrodes symmetrically. In addition, we found the change of the connected site will decrease the spin-resolved currents of the phenalenyl-based molecular device drastically, but had no longer any influence with the pyrene-based molecular device. The results will be helpful for us to further understand the transfer of the spin-carriers in the spintronic systems. (C) 2017 Elsevier Ltd. All rights reserved.
语种：
英文
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The effect of different hydrogen terminations on the structural and electronic properties in the triangular array graphene nanomeshes
作者：
Tang, G. P.* ;Zhang, Z. H.* ;Deng, X. Q.;Fan, Z. Q.;Zhang, H. L.;...
期刊：
RSC Advances ,2017年7(15):8927-8935 ISSN：2046-2069
通讯作者：
Tang, G. P.;Zhang, Z. H.
作者机构：
[Tang, G. P.; Zhang, Z. H.; Zhang, H. L.; Fan, Z. Q.; Sun, L.; Deng, X. Q.] Changsha Univ Sci & Technol, Inst Nanomat & Nanostruct, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Tang, GP; Zhang, ZH] C;Changsha Univ Sci & Technol, Inst Nanomat & Nanostruct, Changsha 410114, Hunan, Peoples R China.
摘要：
Constructing periodic nanoscale holes on graphene to form graphene nanomeshes (GNMs) is an effective way for opening band gaps. The effect of different hydrogen terminations on the structural and electronic properties in the triangular array graphene nanomeshes is investigated systematically from first-principles. The calculated results from the formation energy, Gibbs free energy, and phonon band structure reveal that the di-hydrogenated sp<sup>3</sup>hybridization is the most favorable structure for the hole edges of GNMs except that the other hydrogen terminations may be stable under extremely-poor hydrogen conditions. The electronic properties of GNMs are very sensitive to edge hydrogen terminations, the GNM could be a semimetal, semiconductor, magnetic half-semimetal, or Bipolar Magnetic Semiconductor (BMS) by varying the edge hydrogen terminations, and the GNMs terminated by di-hydrogenation could open a sizable band gap due to the stronger on-site potential between holes, while the gap width could be tuned between semimetallic and semiconducting states by varying the neck width. ©The Royal Society of Chemistry.
语种：
英文
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Redox control of magnetic transport properties of a single anthraquinone molecule with different contacted geometries
作者：
Fan, Zhi-Qiang;Sun, Wei-Yu;Jiang, Xiang-Wei* ;Zhang, Zhen-Hua* ;Deng, Xiao-Qing;...
期刊：
Carbon ,2017年113:18-25 ISSN：0008-6223
通讯作者：
Zhang, Zhen-Hua;Jiang, Xiang-Wei
作者机构：
[Sun, Wei-Yu; Deng, Xiao-Qing; Tang, Gui-Ping; Zhang, Zhen-Hua; Xie, Hai-Qing; Fan, Zhi-Qiang] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.;[Jiang, Xiang-Wei; Fan, Zhi-Qiang] Chinese Acad Sci, State Key Lab Superlattices & Microstruct, Inst Semicond, Beijing 100083, Peoples R China.;[Long, Meng-Qiu] Cent S Univ, Sch Phys & Elect, Changsha 410083, Hunan, Peoples R China.
通讯机构：
[Zhang, Zhen-Hua; Jiang, Xiang-Wei] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.;Chinese Acad Sci, State Key Lab Superlattices & Microstruct, Inst Semicond, Beijing 100083, Peoples R China.
摘要：
Controlling magnetic transport through a single molecule remains one of the most fundamental challenges of spin electronics. Here, we investigate the effects of the redox reaction on the magnetic transport properties of a single anthraquinone (AQ) molecule connected to zigzag graphene nanoribbon electrodes by using the non-equilibrium Green's function formalism with density functional theory. Two kinds of contacted types, isomeric AQ-14 and AQ-15, are considered in this work. The results show the excellent spin-filtering with 100% spin filtering efficiency can be found in AQ-14 molecular device. Redox reaction on the molecule doesn't affect its spin filtering behavior. After the contacted type changing, the spin-filtering behavior is only found in AQ-15 molecular device at the reduced state. When the molecule is oxidized, the α-spin current of the device is reduced dramatically leading to the absence of the spin-filtering behavior. More importantly, the on-off of the α-spin electronic conductance of AQ-15 induced by redox reaction can allow it be designed as a spin current switching.
语种：
英文
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基于网络教学平台的大学物理实验教学改革与实践
作者：
范志强;彭金池;唐贵平;邓敏;邓小清
期刊：
教育教学论坛 ,2017年(31):99-100 ISSN：1674-9324
作者机构：
长沙理工大学物理与电子科学学院,长沙,410114;[邓敏; 唐贵平; 彭金池; 邓小清; 范志强] 长沙理工大学
关键词：
大学物理实验;网络教学平台;教学模式
摘要：
本文对目前大学物理实验教学模式的现状及问题进行了分析，阐‘述了．网络教学平台在大学物理实验教学中的重要作用，并对大学物理实验的教学方法和考核方式进行探索与实践。
语种：
中文
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界面铁掺杂锯齿形石墨烯纳米带的自旋输运性能
作者：
Deng Xiao-Qing* ;Sun Lin;Li Chun-Xian
期刊：
物理学报 ,2016年65(6):068503-1-068503-07 ISSN：1000-3290
通讯作者：
Deng Xiao-Qing
作者机构：
[Deng Xiao-Qing; Sun Lin; Li Chun-Xian] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Peoples R China.
通讯机构：
[Deng Xiao-Qing] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Peoples R China.
关键词：
石墨烯纳米带;自旋输运;自旋过滤效应;第一性原理方法
摘要：
基于密度泛函理论第一原理系统研究了界面铁掺杂锯齿(zigzag)形石墨烯纳米带的自旋输运性能,首先考虑了宽度为4的锯齿(zigzag)形石墨烯纳米带,构件了4个纳米器件模型,对应于中心散射区的长度分别为N=4, 6, 8和10个石墨烯单胞的长度,铁掺杂在中心区和电极的界面.发现在铁磁(FM)态,四个器件的β自旋的电流远大于α自旋的电流,产生了自旋过滤现象;而界面铁掺杂的反铁磁态模型,两种电流自旋都很小,无法产生自旋过滤现象;进一步考虑电极的反自旋构型,器件电流显示出明显的自旋过滤效应.探讨了带宽分别为5和6的纳米器件的自旋输运性能,中心散射区的长度为N=6个石墨烯单胞的长度, FM态下器件两种自旋方向的电流值也存在较大的差异, β自旋的电流远大于α自旋电流.这些结果表明:界面铁掺杂能有效调控锯齿形石墨烯纳米带的自旋电子,对于设计和发展高极化自旋过滤器件有重要意义.
语种：
中文
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Transport properties for carbon chain sandwiched between heteroatom-doped carbon nanotubes with different doping sites
作者：
Liu, Wenjiang;Deng, Xiaoqing* ;Cai, Shaohong*
期刊：
Magnetism and Magnetic Materials ,2016年6(7):075103 ISSN：2158-3226
通讯作者：
Cai, Shaohong;Deng, Xiaoqing
作者机构：
[Liu, Wenjiang] Guizhou Univ, Big Data & Informat Engn Coll, Guiyang 550025, Peoples R China.;[Cai, Shaohong; Liu, Wenjiang] Guizhou Univ Finance & Econ, Guiyang 550025, Peoples R China.;[Deng, Xiaoqing] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Cai, Shaohong] G;[Deng, Xiaoqing] C;Guizhou Univ Finance & Econ, Guiyang 550025, Peoples R China.;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
关键词：
ab initio calculations;carbon nanotubes;doping;electrodes;rectification;sandwich structures
摘要：
The First-principles calculation is used to investigate the transport properties of a carbon chain connected with N-and/or B-doped caped carbon nanotube acting as electrodes. The I-V curves of the carbon chain are affected by the N/B doping sites, and rectifying behavior can be obtained distinctly when the carbon chain is just connected onto two doping atom sites (N- chain-B), and a weak rectification occurs when N (B) doping at other sites. Interestingly, the spin-filtering effects exist in the junction when it is doped at other sites, undoped system, or N-terminal carbon chains. However, no this behavior is found in N-chain-B and B-chain-B systems. The analysis on the transmission spectra, PDOS, LDOS, spin density, and the electron transmission pathways give an insight into the observed results for the system. © 2016 Author(s).
语种：
英文
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The design of bipolar spin filtering junction in zigzag silicene nanoribbons
作者：
Deng, X. Q.* ;Zhang, Z. H.* ;Tang, G. P.;Fan, Z. Q.;Sun, L.;...
期刊：
Organic Electronics ,2016年37:245-251 ISSN：1566-1199
通讯作者：
Deng, X. Q.;Zhang, Z. H.
作者机构：
[Deng, X. Q.; Zhang, Z. H.; Li, C. X.; Zhang, H. L.; Tang, G. P.; Fan, Z. Q.; Sun, L.] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Deng, XQ; Zhang, ZH] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
关键词：
Crystal atomic structure;Electron transport properties;Electronic structure;Energy gap;Heterojunctions;Hydrogenation;Magnetic semiconductors;Nanoribbons;Wide band gap semiconductors;Bonding networks;Electron transmission spectrums;First-principles simulations;Semiconducting behavior;Spin configurations;Spin filtering;Spin-dependent electron transport;Spin-polarized effects;Silicene
摘要：
We performed first-principles simulation on the electronic structure of zigzag silicene nanoribbons (ZSiNRs), and found that semi-hydrogenation can break the extended π-bonding network of silicene, leaving the electrons in the unsaturated Si atoms localized and unpaired, and ferromagnetic semiconducting behavior can be obtained. While the fully hydrogenated ZSiNRs are found to be energetically degenerate and show wide band-gap semiconductor feature. Then, we designed and investigated the spin-dependent electron transport of a heterostructure, consisting of semi-hydrogenation ZSiNRs and ZSiNRs. The results show a perfect dual spin filtering effect at the parallel and antiparallel spin configuration with large bias range. The spin dependent electron transmission spectrum, band structure, transmission pathway, and the molecularly projected self-consistent Hamiltonian state are employed to investigate the physical origin of the spin-polarized effect. © 2016 Elsevier B.V.
语种：
英文
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Modulation of the spin transport properties of the iron-phthalocyanine molecular junction by carbon chains with different connection sites
作者：
Deng, X. Q.* ;Zhang, Z. H.* ;Tang, G. P.;Fan, Z. Q.;Sun, L.;...
期刊：
Organic Electronics ,2016年35:1-5 ISSN：1566-1199
通讯作者：
Deng, X. Q.;Zhang, Z. H.
作者机构：
[Deng, X. Q.; Zhang, Z. H.; Li, C. X.; Tang, G. P.; Fan, Z. Q.; Sun, L.] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Deng, XQ; Zhang, ZH] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
关键词：
Carbon;Chains;Iron;Molecules;Negative resistance;Transport properties;Iron phthalocyanines;Local density of state;Molecular junction;Negative differential resistances;Non equilibrium green's function method;Spin filtering;Transmission spectrums;Transmitting paths;Density functional theory
摘要：
Based on the non-equilibrium Green's function method combined with the density functional theory, the spin transport properties of an iron-phthalocyanine (FePc) molecule connected to two Au electrodes by carbon chains are investigated, and three kinds of connecting position between FePc molecule and carbon chains are considered. It is found that the spin filtering effect and the negative differential resistance (NDR) behavior in these systems can be achieved in the calculated bias region. However, the efficiency and the bias region of spin filtering are affected significantly by the connecting positions. The above results are explained by the spin-resolved transmission spectrum, electron transmitting path, molecular projected self consistent Hamiltonian state, and the local density of states (LDOS) analyses. Our calculations demonstrate a promising modification for developing molecule spintronic devices. © 2016 Elsevier B. V. All rights reserved.
语种：
英文
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硼氮掺杂碳纳米管的电子输运性能
作者：
邓小清;孙琳;李春先
期刊：
邵阳学院学报(自然科学版) ,2016年13(2):21-24 ISSN：1672-7010
作者机构：
长沙理工大学物理与电子科学学院，湖南长沙，410114;[李春先; 孙琳; 邓小清] 长沙理工大学
关键词：
纳米管;整流效应;第一性原理方法
摘要：
基于密度泛函理论的第一性原理,我们采用碳纳米管做电极,且纳米管一端与半个C60连接,两纳米管之间用烷链连接,构建了电子器件,通过在C60上进行硼氮掺杂,发现器件具有明显的整流效应.进一步研究了不同长度烷链的电子输运性能,发现选择合适的碳链长度,有利于提高器件的整流系数.
语种：
中文
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Effect of electrode twisting on electronic transport properties of atomic carbon wires
作者：
Fan, Z. Q.* ;Zhang, Z. H.;Deng, X. Q.;Tang, G. P.;Yang, C. H.;...
期刊：
Carbon ,2016年98:179-186 ISSN：0008-6223
通讯作者：
Fan, Z. Q.
作者机构：
[Zhu, H. L.; Tang, G. P.; Fan, Z. Q.; Zhang, Z. H.; Sun, L.; Deng, X. Q.; Yang, C. H.] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Fan, Z. Q.] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410004, Hunan, Peoples R China.
摘要：
We investigate the electron transport properties in atomic carbon wires between two zigzag graphene nanoribbon (ZGNR) electrodes by applying nonequilibrium Green's functions in combination with the density-functional theory. It shows that the ZGNR electrode twisting can modulate the conductance of the atomic carbon wire-graphene junctions remarkably. Typical currents of devices with odd carbon wires are much higher than currents of devices with even carbon wires to exhibit even-odd behavior. The negative differential resistance behaviors are only found in the devices with odd carbon wires. When the right ZGNR electrode is twisted, the curvatures of the current-voltage characteristics change remarkably upon twisted angles. The current will decrease by up to 5 orders of magnitude when the twisted angle reaches to 90°. That means the atomic carbon wire-graphene junctions can be made as a mechanical switching. © 2015 Elsevier Ltd. All rights reserved.
语种：
英文
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Magnetism and magnetic transport properties of the polycrystalline graphene nanoribbon heterojunctions
作者：
Wang, D.;Zhang, Z. H.* ;Deng, X. Q.;Fan, Z. Q.;Tang, G. P.
期刊：
Carbon ,2016年98:204-212 ISSN：0008-6223
通讯作者：
Zhang, Z. H.
作者机构：
[Wang, D.; Tang, G. P.; Fan, Z. Q.; Zhang, Z. H.; Deng, X. Q.] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Zhang, Z. H.] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
摘要：
The polycrystalline structures for graphene are practically unavoidable by the currently existing growth routes, thus the scattering issue of electrons by grain boundary (GBs) becomes a theoretical and an experimental relevant one. Here, magnetic transport properties of the polycrystalline graphene nanoribbons (PGNRs) with a zigzag-armchair-zigzag structure are investigated systematically. It shows that GBs can induce significant localized electron states and magnetic ordering in the region consisting of GBs and armchair segment, and the interdomain electronic transmission across the GBs is transparent or blocked completely depending on the spin direction (α or β) of electrons as well as the microscopic details and relative orientation of GBs, which causes a special spin polarization for the magnetic transport. Especially, the perfect spin-filtering, spin-rectifying, and giant magnetoresistance effects can be realized simultaneously in such heterojunctions. These novel features can be rationalized by the spin splitting of molecular levels as well as the delocalization degree and parity limitation of molecular orbital wave functions in the scattering region serving as an extended molecule. Also shown is that PGNR-based heterojunctions possess a large range of magnetic behaviors with variation of its geometrical size. © 2015 Elsevier Ltd. All rights reserved.
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英文
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Improving the bias range for spin-filtering by selecting proper electrode materials
作者：
Deng, X. Q.* ;Zhang, Z. H.;Yang, C. H.
期刊：
RSC Advances ,2015年5(21):15812-15817 ISSN：2046-2069
通讯作者：
Deng, X. Q.
作者机构：
[Zhang, Z. H.; Deng, X. Q.; Yang, C. H.] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Deng, X. Q.] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
摘要：
Using the non-equilibrium Green's function method combined with density function theory, we investigate the spin transport for carbon chains connected to electrodes of different materials. When a carbon chain is linked to the C-H (C-H<inf>2</inf>) bonded edges of H<inf>2</inf>-ZGNR-H, the carbon chain displays a net spin polarization with a net magnetic moment of 1.367 μB (-0.935 μB) for the C-H (C-H<inf>2</inf>) bonded edge contacts, but the directions of the net magnetic moment are opposite, and the latter system shows a larger spin conductance. Then, we choose N-doped H<inf>2</inf>-ZGNR-H as the left electrode, and the right electrode is replaced with a single-capped carbon nanotube, armchair graphene nanoribbon (AGNR), or gold electrode. The conductance and the bias range for perfect spin-filtering of these systems shows obvious differences: the carbon nanotube (Au) system shows weaker conductance, and the AGNR system shows the largest bias range for perfect spin-filtering. This journal is ©2015 The Royal Society of Chemistry.
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英文
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The design of bipolar spin semiconductor based on zigzag–edge graphene nanoribbons
作者：
Deng, X. Q.* ;Zhang, Z. H.;Tang, G. P.;Fan, Z. Q.;Yang, C. H.;...
期刊：
Carbon ,2015年94:317-325 ISSN：0008-6223
通讯作者：
Deng, X. Q.
作者机构：
[Tang, G. P.; Fan, Z. Q.; Zhang, Z. H.; Sun, L.; Deng, X. Q.; Yang, C. H.] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.;[Deng, X. Q.] 960,2nd Sect,Wanjiali South RD, Changsha, Hunan, Peoples R China.
通讯机构：
[Deng, X. Q.] 9;960,2nd Sect,Wanjiali South RD, Changsha, Hunan, Peoples R China.
摘要：
Using first-principle methods, we investigate the magnetism properties of zigzag-edge graphene nanoribbons (ZGNRs) with a nanopore, and find that edges of such a nanopore show important effects although the electron transport is mainly along the outer edge of ZGNR. The robust bipolar spin semiconductor can be obtained when the edges of such a nanopore are varied, where both spin states have a gap but can relatively shift. We speculate that bipolar spin semiconductor behavior is related with two factors: broken inner edge states and width of electrode. A series of models are considered: 6-ZGNRs with only one edge occupied by one triangle protrusion (TP), are connected with different width ZGNR electrodes. With the increase the electrode width along the TP edge direction, the systems show the following behavior in turn: spin metallicity, spin gapless semiconductor, and bipolar spin semiconductor. Finally, we show that the half-metallicity is realizable when electric fields are applied across the ZGNR with a nanopore, and their magnetic properties can be controlled by the external electric field. These findings suggest a new possibility for developing nanometer-scale carbon spintronic devices. ©2015 Elsevier Ltd. All rights reserved.
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英文
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Rectifying Performance and Negative Differential Resistance Behavior of Doping Atoms Effect in Polyphenyls
作者：
Liu, Wenjiang* ;Cai, Shaohong;Deng, Xiaoqing
期刊：
Journal of Electronic Materials ,2015年44(2):667-674 ISSN：0361-5235
通讯作者：
Liu, Wenjiang
作者机构：
[Liu, Wenjiang] Guizhou Univ, Big Data & Informat Engn Coll, Guiyang 550025, Peoples R China.;[Cai, Shaohong; Liu, Wenjiang] Guizhou Univ Finance & Econ, Guiyang 550025, Peoples R China.;[Deng, Xiaoqing] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Liu, Wenjiang] G;Guizhou Univ, Big Data & Informat Engn Coll, Guiyang 550025, Peoples R China.
关键词：
Doping (additives);Hydrocarbons;Molecular electronics;Negative resistance;Paraffins;Electrostatic potential distribution;Hamiltonian eigenstates;Negative differential resistances;Projected density of state;Rectification ratio;Rectifying;Transmission spectrums;Voltage characteristics;Density functional theory
摘要：
The properties of two polyphenyls doped with nitrogen and boron atoms, which are connected by an alkane chain, are investigated by the non-equilibrium Green’s function method combined with the density functional theory. It has been found that the doped sites have significant effects on the current–voltage characteristics. For models with the N(B) near the alkane chain, the rectification ratio is smaller, but the rectifying performance of models with the N(B) far away from the alkane chain is tremendously enhanced and rectification ratios can reach 280, alongside negative differential resistance behavior. The mechanisms for these phenomena are explained by transmission spectra, the molecular projected self-consistent Hamiltonian eigenstates, electrostatic potential distribution, and projected density of states. © 2014, The Minerals, Metals & Materials Society.
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英文
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