摘要：
Using nonequilibrium Green's function combined with density functional theory, we investigate the transport properties of a single perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) molecular device before and after adsorbing single heavy metal atoms Ni, Pd, Cd, Cu, Zn, and Ag. We find that the adsorption of a single Ni or Pd atom has a slight modulation on the I–V characteristic of the junction. However, the adsorptions of a single Cd, Cu, Zn, and Ag atom can shift the transmission spectra of the junctions obviously leading to the large decrease in the conductance. The results of this study have certain guiding significance for the practical preparation of heavy metal atom sensors for organic molecules in the future.
期刊：
PHYSICAL CHEMISTRY CHEMICAL PHYSICS,2020年22(7):4080-4085 ISSN：1463-9076
通讯作者：
Qiu, Ming
作者机构：
[Han, Lingyun; Xia, Ying; Shuai, Ling; Wang, Yiping; Ma, Yao; Qiu, Ming] Cent China Normal Univ, Inst Nanosci & Nanotechnol, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.;[Zhang, Zhenhua] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Peoples R China.;[Leung, Michael K. H.] City Univ Hong Kong, Abil R&D Energy Res Ctr, Sch Energy & Environm, Hong Kong, Peoples R China.
通讯机构：
[Qiu, Ming] C;Cent China Normal Univ, Inst Nanosci & Nanotechnol, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.
摘要：
Many organic molecules have unique magnetic properties and can potentially serve as excellent molecular spin devices, which is worth exploring deeply. Here, the spin transport properties of Mn, Fe, Co and Cu porphyrin dimer devices are investigated based on the first principles method. The spin filtering efficiencies of these molecular devices are maintained at 100% within certain applied voltage ranges and magnetoresistance ratios are higher than 10(8)% which increase as the voltage increases. To explain the excellent spin-filtering and giant magnetoresistance effects, analysis of spin electron densities and transmission spectra indicates that magnetic properties are mainly contributed by the metal atoms and their neighbouring N atoms. From the transmission pathway studies, spin electrons come mainly through the pi-conjugated structure of the metal porphyrin ring. Interestingly, in the Cu porphyrin dimer device, magnetic moments of the Cu-N structure in the Cu porphyrin dimer device show spin behaviors different from those of Mn, Fe and Co porphyrin dimer devices.
作者机构：
[Sun, Lin; Li, Mo] Cent S Univ, Sch Phys & Elect, Changsha 410083, Hunan, Peoples R China.;[Zhang, Zhen Hua; Sun, Lin] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.;[Sun, Lin] Changsha Univ Sci & Technol, Hunan Prov Higher Educ Key Lab Modeling & Monitor, Changsha 410114, Hunan, Peoples R China.;[Wang, Hao] Shenzhen Univ, Coll Mechatron & Control Engn, Guangdong Prov Key Lab Micro Nano Optomechatron E, Shenzhen 518060, Peoples R China.;[Li, Mo] Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA.
通讯机构：
[Li, Mo] C;[Wang, Hao] S;[Li, Mo] G;Cent S Univ, Sch Phys & Elect, Changsha 410083, Hunan, Peoples R China.;Shenzhen Univ, Coll Mechatron & Control Engn, Guangdong Prov Key Lab Micro Nano Optomechatron E, Shenzhen 518060, Peoples R China.
摘要：
Using first-principles calculation based on density-functional theory, the electronic properties of monolayer black phosphorus nanoribbons (PNRs) with and without punched nanoholes (PNRPNHs) and their mechanical stability are studied systematically. We show that while the perfect PNRs and the PNRPNHs have similar properties as semiconductors in both armchair-edge PNR and zigzag-edge PNR structures, the nanoholes can lead to changes in the electronic structure: the zigzag-edge PNRPNH undergoes a direct-to-indirect bandgap transition while the armchair-edge PNRPNH still retains a direct bandgap but with a significant increase in the bandgap as compared to the perfect PNRs. We found also that nanoholes have little influence on the structural stability of PNRs; but the applied external transverse electric field and strain can be more effective in modulating the bandgaps in the PNRPNHs. These new findings show that PNRs are a promising candidate for future nanoelectronic and optoelectronic applications.
摘要：
Exploring half-metallic nanostructures is a crucial solution for developing high-performance spintronic devices. Black phosphorene is an emerging two-dimensional material possessing strong anisotropic band structure and high mobility. Based on the first principles calculations, we investigated the electronic and magnetic properties of zigzag phosphorene nanoribbons (ZPNRs) with three different functionalization groups (OH/CN, OH/NO2, NH2/NO2) at the edges. We find that the interplay between edge functionalization and edge oxidation can induce the half metal phase in the ZPNRs, and the half metal phase can be controlled by the external transverse in-plane electric field and the proportion of the functional groups and edge oxidation. The results may pave a new way to construst nanoscale spintronic devices based on black phosphorene nanoribbons.
摘要：
One-dimensional phosphorus nanotubes (PNTs) are important derivatives of phosphorene. Herein, the magneto-electronic properties for PNTs doped with low-concentration transition metals (TM) (Fe, Co, and Ni) both in their inner and outer layers were investigated in detail. TM-PNTs are very stable with high structural integrity and versatile magnetic properties. In particular, some important magnetic properties such as half-metallic and dilute magnetic semiconducting behaviors can be observed, which are the basis of the application of TM-PNTs in spintronics. Furthermore, the electric field can induce magnetic phase transitions and demagnetization can occur under a very low electric field due to Co-doping in the outer layer of the PNTs. This interesting feature is very attractive for constructing electric-field-controllable magnetic/nonmagnetic switch devices that are operated in two possible states.
作者：
Hu, R.;Fan, Z. Q.;Fu, C. H.;Nie, L. Y.;Huang, W. R.;...
期刊：
Carbon,2018年126:93-104 ISSN：0008-6223
通讯作者：
Zhang, Z. H.
作者机构：
[Fan, Z. Q.; Huang, W. R.; Fu, C. H.; Zhang, Z. H.; Hu, R.; Nie, L. Y.] Changsha Univ Sci & Technol, Inst Nanomat & Nanostruct, 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：
Tuning the magneto-electronic properties of graphene-based structures into distinguished performance is an interesting but challenging work. To address this issue, we here construct several chain-like 1D nanostructures by stitching zigzag-edged triangular graphene nanoflakes with different manners and subsequently oxidized at edges. The high stability of these structures is identified by the calculated edge adsorption energy, phonon spectrum, and molecular dynamics simulations. Unlike edge-hydrogenation case, termination oxygen atoms here are highly magnetized and can control such 1D chain magneto-electronic features substantially. The calculations predict that such 1D chains are very versatile, and behaviors are sensitive to geometry, likely acting as a ferromagnetic metal and half-metal and bipolar magnetic semiconductor, or an antiferromagnetic metal and semiconductor. In particular, such a ferromagnetic half-metallic feature can occur in the ground state and possesses a wide bandgap, suggesting that they are excellent magnetic materials. The calculated spin transport characteristics reveal that such a chain-based device promises not only a perfect double spin-filtering effect, but also an excellent dual spin diode feature and a giant magnetoresistance (GMR) effect. The advantages over graphene nano-ribbons are thus expected. (c) 2017 Elsevier Ltd. All rights reserved.
期刊：
PHYSICAL CHEMISTRY CHEMICAL PHYSICS,2017年19(6):4469-4477 ISSN：1463-9076
通讯作者：
Zhang, Z. H.
作者机构：
[Yuan, P. F.; Fan, Z. Q.; Zhang, Z. H.; Liu, J.] Changsha Univ Sci & Technol, Inst Nanomat & Nanostruct, 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：
The structural and magneto-electronic properties and electric field-mediated effects for zigzag boron nitride nanoribbons (ZBNNRs) terminated with typical transition metal (TM) atoms (TM-ZBNNRs) are investigated systematically. Our work demonstrates that ZBNNRs form strong bonds with all studied termination atoms. The strong interactions and large orbital hybridizations of TM atoms to the ribbon make the magnetic anisotropy enhanced significantly, favorably to stabilize magnetism. The spin-split features for such hybridized structures can occur in most of the magnetic configurations, leading to a large magnetic moment. Higher spin polarization can be found in the ferromagnetic (FM) state. In particular, spin polarization exceeding 90% at the Fermi level can be achieved for Fe-ZBNNRs when an in-plane transverse electric field is applied. These results might be of interest from the prospects of both fundamental science and its potential applications.
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.
