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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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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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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Spin-filtering and rectifying effects for Al-doped zigzag-edged silicene nanoribbons with asymmetric edge hydrogenation
作者：
Deng, X. Q.* ;Zhang, Z. H.* ;Fan, Z. Q.;Tang, G. P.;Sun, L.;...
期刊：
Organic Electronics ,2016年32:41-46 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：
Density functional theory;Hydrogenation;Nanoribbons;Negative resistance;Silicene;Spin polarization;Negative differential resistances;Non equilibrium green's function method;Rectifying effect;Rectifying performance;Spin filtering;Spin polarized currents;Spin-polarized density functional theory;Spintronic device;Silicon compounds
摘要：
Spin transport features of the Al-doping zigzag-edged silicene nanoribbons (ZSiNRs) are investigated by using the nonequilibrium Green's function method and the spin-polarized density functional theory, where ZSiNRs are Si-H2 bonded at one edge while Si-H bonded at the other to form an asymmetric edge hydrogenation. It is found that a perfect spin filtering effect (100%) in such ZSiNRs can be achieved in the calculated bias region. The rectifying performance of spin-polarized currents with a ratio larger than 105 can be achieved by changing the position of the doping atoms. Moreover, the negative differential resistance (NDR) effect is also observed in the spin-polarized current. Our calculation suggests Al-doping ZSiNRs with the asymmetric edge hydrogenation hold promise for multifunctional spintronic devices. © 2016 Elsevier B.V.
语种：
英文
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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.
语种：
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.
语种：
英文
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Spin filtering behaviors for a carbon chain connected with armchair- and zigzag-edged graphene nanoribbon electrodes
作者：
Yang, C. H.* ;Deng, X. Q.;Tang, G. P.;Fan, Z. Q.
期刊：
Solid State Communications ,2015年203:26-30 ISSN：0038-1098
通讯作者：
Yang, C. H.
作者机构：
[Tang, G. P.; Fan, Z. Q.; Deng, X. Q.; Yang, C. H.] Changsha Univ Sci & Technol, Sch Phy & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Yang, C. H.] C;Changsha Univ Sci & Technol, Sch Phy & Elect Sci, Changsha 410114, Hunan, Peoples R China.
关键词：
Spin filtering;Graphene;Carbon chain;First-principles calculation
摘要：
Using the non-equilibrium Green's function method combined with the density functional theory, we investigate the spin transport properties of carbon chains connected with armchair- and zigzag-edged graphene nanoribbon (ZGNR) electrodes at finite bias with the parallel magnetism configuration. When spin polarized electrons are injected into carbon chains from the ZGNR electrode, the beta-spin current is nearly zero, while the alpha-spin current shows large values in the calculated bias region, thus the spin polarization 100% can be achieved, which is a promising pathway for developing a spin filter. (C) 2014 Elsevier Ltd. All rights reserved.
语种：
英文
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Reversible switching in gold-atom–organic-molecule complex induced by reversible bond formation
作者：
Fan, Zhi-Qiang;Zhang, Zhen-Hua* ;Xie, Fang;Deng, Xiao-Qing;Tang, Gui-Ping;...
期刊：
Organic Electronics ,2015年18:101-106 ISSN：1566-1199
通讯作者：
Zhang, Zhen-Hua
作者机构：
[Deng, Xiao-Qing; Tang, Gui-Ping; Zhang, Zhen-Hua; Yang, Chang-Hu; Fan, Zhi-Qiang] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410004, Hunan, Peoples R China.;[Xie, Fang] Yichun Univ, Phys Sci & Engn Technol Coll, Yichun 336000, Peoples R China.;[Chen, Ke-Qiu] Hunan Univ, Dept Appl Phys, Changsha 410082, Hunan, Peoples R China.;[Chen, Ke-Qiu] Key Lab Micronano Phys & Technol Hunan Prov, Changsha 410082, Hunan, Peoples R China.
通讯机构：
[Zhang, Zhen-Hua] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410004, Hunan, Peoples R China.
关键词：
Chemical bonds;Gold compounds;Graphene;Graphite electrodes;Molecules;Nanoribbons;Switching;Transport properties;Electronic transport;Electronic transport properties;Graphene electrodes;Graphene nanoribbons;Molecular device;Non-equilibrium Green's function;Reversible switching;Switching behaviors;Density functional theory
摘要：
By applying nonequilibrium Green's functions in combination with the density-functional theory, we investigate the electronic transport properties of a molecule PTCDA sandwiched between two Au electrodes. The results show that the adsorption of an Au atom can modulate the conductance of the Au-PTCDA-Au junction remarkably. The reversible switching behavior can be found in this device, arising from the reversible bond formation between the Au adatom and the PTCDA molecule, which is in line with the experimental results. However, the switching behavior of the molecule PTCDA induced by reversible bond formation disappeared when the Au electrode is replaced by the armchair-edge graphene nanoribbons. That means the graphene electrodes with armchair termination deeply affect the electronic transport properties of the molecule PTCDA at small bias voltages. © 2015 Published by Elsevier B.V.
语种：
英文
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Magnetic transport properties of a trigonal graphene sandwiched between graphene nanoribbon electrodes
作者：
Li, J.;Zhang, Z. H.* ;Deng, X. Q.;Fan, Z. Q.;Tang, G. P.
期刊：
Carbon ,2015年93:335-341 ISSN：0008-6223
通讯作者：
Zhang, Z. H.
作者机构：
[Tang, G. P.; Li, J.; Fan, Z. Q.; Zhang, Z. H.; Deng, X. Q.] Changsha Univ Sci & Technol, Inst Nanomat & Nanostruct, Changsha 410114, Hunan, Peoples R China.;[Tang, G. P.; Fan, Z. Q.; Zhang, Z. H.; Deng, X. Q.] Changsha Univ Sci & Technol, Hunan Prov Higher Educ Key Lab Modeling & Monitor, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Zhang, Z. H.] C;Changsha Univ Sci & Technol, Inst Nanomat & Nanostruct, Changsha 410114, Hunan, Peoples R China.
摘要：
Magnetic transport behaviors of a zigzag-edge trigonal graphene (ZTG) constructed as a nanodevice with zigzag graphene nanoribbon (ZGNR) electrodes are investigated, and various magnetic configurations are considered. It is found that excellent magnetic device natures, such as the perfect (100%) spin polarization in a large bias region, spin-resolved rectification ratios approaching 105, and the giant magnetoresistance effect up to 1015%, can be achieved, which is indeed an extremely high value as compared with previously reported theoretical one, ∼107%, for complete ZGNR-based magnetic devices and experimental ones, ∼104%, for the MgO tunnel junction. This can be attributed to unique transmission features due to the strong modulating ability of ZTG for the magnetic transport. These results suggest that the ZTG might possess some advantages in nature for developing magnetic devices. © 2015 Elsevier Ltd. All rights reserved.
语种：
英文
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Electronic structures and transport properties of armchair graphene nanoribbons by ordered doping
作者：
Liu, J.;Zhang, Z. H.* ;Deng, X. Q.;Fan, Z. Q.;Tang, G. P.
期刊：
Organic Electronics ,2015年18:135-142 ISSN：1566-1199
通讯作者：
Zhang, Z. H.
作者机构：
[Tang, G. P.; Fan, Z. Q.; Zhang, Z. H.; Liu, J.; 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.
关键词：
Atoms;Crystal atomic structure;Electron transport properties;Electronic structure;Energy gap;Molecules;Nanoribbons;Semiconductor doping;Transport properties;Armchair graphene nanoribbons;Atom-projected density;Doping positions;First principles method;Graphene nanoribbons;Impurity atoms;N-doped;n-Type doping;Graphene
摘要：
Based on the first-principles method, the electronic structures and transport properties of armchair graphene nanoribbons (AGNRs) with ordered doping of B atoms or N atoms or BN molecules are studied systematically. It shows that the AGNRs may be a metal or a semiconductor depending on B or N atom-doping positions, and the calculated atom-projected density of states (atom-PDOS) indicates that B or N impurity atoms can induce the new lowest conduction band (LCB) or the highest valence band (HVB). More interestingly, as compared with the intrinsic AGNR device, the current in the B- or N-doped AGNR device with the most energetically favorable state is extremely small, completely different from a macroscopic Si semiconductor with p-type or n-type doping, which always leads to a significant increase in current. Also shown is that the doping with BN molecules generally increases the bandgap of the AGNR regardless of the doping position, but the size of these bandgaps depends on the doping positions. The current in the BN-doped AGNR device is also decreased greatly in comparison with that for the intrinsic AGNR device. © 2015 Elsevier B.V.
语种：
英文
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Tuning spin polarization and spin transport of zigzag graphene nanoribbons by line defects
作者：
Tang, G. P.* ;Zhang, Z. H.;Deng, X. Q.;Fan, Z. Q.;Zhu, H. L.
期刊：
PHYSICAL CHEMISTRY CHEMICAL PHYSICS ,2015年17(1):638-643 ISSN：1463-9076
通讯作者：
Tang, G. P.
作者机构：
[Zhu, H. L.; Tang, G. P.; Fan, Z. Q.; Zhang, Z. H.; Deng, X. Q.] Changsha Univ Sci & Technol, Inst Nanomat & Nanostruct, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Tang, G. P.] C;Changsha Univ Sci & Technol, Inst Nanomat & Nanostruct, Changsha 410114, Hunan, Peoples R China.
摘要：
From first-principles methods, the spin-dependent electronic properties of zigzag-edged graphene nano-ribbons (ZGNRs) with a line defect (558-defect) are investigated systematically and compared to those of the pristine ZGNR. Results show that the line defect possesses an obvious tuning effect on the spin-polarization of the edge carbon atoms of the defective ZGNRs, and the spin-polarization and spin-transport are sensitive to the position of line defects. The defective ZGNRs can realize a transition from antiferromagnetism (AFM) to ferrimagnetism and ferromagnetism (FM) via changing the position of line defects from the center to the zigzag edge of ZGNRs. More importantly, when the line defect is located at the one edge, the defective ZGNRs exhibit the long-range magnetic ordering at edges with a high Curie temperature up to 276 K, and the defective ZGNR system can generate a high-performance spin-filter effect in the large bias range, 0.0-0.5 V. Such a sensitive modulation for the spin-polarization and spin-transport holds great promise for applications of the graphene-based systems in nano-scale spintronic devices.
语种：
英文
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Magnetic structure and magnetic transport characteristics of nanostructures based on armchair-edged graphene nanoribbons
作者：
Zhu, Z.;Zhang, Z. H.* ;Wang, D.;Deng, X. Q.;Fan, Z. Q.;...
期刊：
Journal of Materials Chemistry C ,2015年3(37):9657-9663 ISSN：2050-7526
通讯作者：
Zhang, Z. H.
作者机构：
[Zhu, Z.; Wang, D.; Tang, G. P.; Fan, Z. Q.; Zhang, Z. H.; Deng, X. Q.] Changsha Univ Sci & Technol, Inst Nanomat & Nanostruct, Changsha 410114, Hunan, Peoples R China.;[Zhu, Z.; Wang, D.; Tang, G. P.; Fan, Z. Q.; Zhang, Z. H.; Deng, X. Q.] Changsha Univ Sci & Technol, Hunan Prov Higher Educ Key Lab Modeling & Monitor, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Zhang, Z. H.] C;Changsha Univ Sci & Technol, Inst Nanomat & Nanostruct, Changsha 410114, Hunan, Peoples R China.
关键词：
Curie temperature;Free energy;Giant magnetoresistance;Gibbs free energy;Graphene;Magnetic devices;Magnetic structure;Magnetism;Magnetoelectronics;Manganese;Nanostructures;Spin polarization;Edge modification;First principles method;Graphene nanoribbons;High Curie temperature;Magnetic transport;Rectification ratio;Spintronic device;Wide band gap;Nanoribbons
摘要：
Exploring half-metallic nanostructures with a high Curie temperature and a wide half-metallic gap is a crucial solution for developing high-performance spintronic devices. Using the first-principles method, we design a new magnetic structure based on edge modification of armchair-edged graphene nanoribbons by Mn and F atoms (AGNR-Mn-F2). It is found that such a structure is an excellent half-metal with a wide bandgap (∼1.2 eV) and a stable magnetic ordering by a very high Curie temperature (Tc > 700 K) as well as being predicted to stably exist in a very large chemical potential range in experiment by the Gibbs free energy. And it is also shown that it possesses an outstanding magnetic device nature, such as a spin polarization of 100% in a very large bias region, a dual spin diode-like rectification ratio up to 105, and a spin-valve feature with a giant magnetoresistance approaching 108%, indicating a promising application for developing spintronic devices. © 2015 The Royal Society of Chemistry.
语种：
英文
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Spin filtering and large magnetoresistance behaviors in carbon chain-zigzag graphene nanoribbon nanojunctions
作者：
Deng, X. Q.* ;Zhang, Z. H.;Tang, G. P.;Fan, Z. Q.;Yang, C. H.
期刊：
Physics Letters A ,2014年378(21):1540-1547 ISSN：0375-9601
通讯作者：
Deng, X. Q.
作者机构：
[Tang, G. P.; Fan, Z. Q.; Zhang, Z. H.; Deng, X. Q.; Yang, C. H.] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Deng, X. Q.] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410004, Hunan, Peoples R China.
关键词：
Graphene;Magnetoresistance;Spin filtering
摘要：
Using the non-equilibrium Green's function method combined with the density functional theory, we investigate the electron and spin transport properties of carbon chains covalently connected with zigzag-edged graphene electrodes at finite bias with the parallel (P) and antiparallel (AP) magnetism configurations. When two zigzag-edged graphene electrodes are H2-ZGNR--H structures, spin filtering effect can be realized only with AP magnetism configuration. While one electrode is replaced with the H-ZGNR-H structure, we observe a dual spin filtering effect with above two magnetism configurations. But the spin transport properties of carbon chains can also be affected by the linking way of the carbon chain ends. Deeper analyses show that the spin-related properties are related to the electrodes, magnetism configurations, and the connection structure between electrodes and carbon chains. (C) 2014 Elsevier B.V. All rights reserved.
语种：
英文
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Electronic and spin transport properties in zigzag silicene nanoribbons with edge protrusions
作者：
Deng, X. Q.* ;Zhang, Z. H.;Tang, G. P.;Fan, Z. Q.;Yang, C. H.
期刊：
RSC Advances ,2014年4(103):58941-58948 ISSN：2046-2069
通讯作者：
Deng, X. Q.
作者机构：
[Tang, G. P.; Fan, Z. Q.; 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：
We investigate the electronic transport properties of zigzag-edged silicene nanoribbons (ZSiNRs) with one or two protrusions at the edges using the density functional theory combined with nonequilibrium Green's function method. It is found that the protrusion generally breaks down the edge state along the same edge, which carries current in the junction. For the ZSiNR having an even number of zigzag chains in its width, the protrusions can increase the conductance except for the case of two symmetric protrusions. For ZSiNRs with an odd number of zigzag chains in its width, the introduction of edge protrusions can suppress currents. We also investigate the spin-dependent transport properties of ZSiNR-based devices with antiparallel (AP) magnetism configuration. Interestingly, only non- and symmetric-protrusion models with a width of an even number of zigzag chains show a perfect spin filter effect. © 2014 The Royal Society of Chemistry.
语种：
英文
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Modulating magnetic ordering of the zigzag-edge trigonal graphene by functionalizations
作者：
Zhang, J. J.;Zhang, Z. H.* ;Tang, G. P.;Deng, X. Q.;Fan, Z. Q.
期刊：
Organic Electronics ,2014年15(7):1338-1346 ISSN：1566-1199
通讯作者：
Zhang, Z. H.
作者机构：
[Zhang, J. J.; 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.
关键词：
Atoms;Bond length;Charge transfer;Graphene;Magnetic semiconductors;Magnetic structure;Magnetism;Nanotechnology;Point defects;Semiconductor doping;Edge modification;Functionalizations;In-depth analysis;Spin-polarized charges;Spintronics device;Stone-Wales defects;Structural deformation;Zigzag-edge trigonal graphene;Spin polarization
摘要：
A pristine zigzag-edge trigonal graphene (ZTG) is a magnetic semiconductor, thus its spin polarization is extremely low. Here, we report the calculated results on enhancing the spin magnetism of a zigzag-edge trigonal graphene (ZTG) by functionalizations, including the heteroatom doping, edge modifications, and introducing topologic defects. It is found that the ZTG features a good tuning ability for functionalizations to improve its spin polarization. When one boron (B) atom is doped to replace one carbon atom in the B sublattice of graphene, a higher spin polarization can be achieved, and the edge modification by Cu, Co, O or B atom can modulate the magnetic ordering significantly due to the spin-polarized charge transfer between the ZTG and terminations, especially for O and Co terminations. And also, the introduced defect (a vacancy and a Stone-Wales defect) can obviously tune local magnetic structures owing to geometrically structural deformations (variations of bond length and bond angle). For these behaviors, in-depth analyses are performed. Our findings suggest that the desirable functionalized ZTG structures might promise importantly potential applications for developing nano-scale spintronics devices. © 2014 Elsevier B.V. All rights reserved.
语种：
英文
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