Spin-Polarized Current of a Transistor in Single Mn12 Molecular Magnets

2007 ◽  
Vol 7 (11) ◽  
pp. 4111-4115
Author(s):  
Joonho Park ◽  
Heok Yang ◽  
K.-S. Park ◽  
Eok-Kyun Lee
Keyword(s):  
Theoretical Calculation ◽  
Single Molecule ◽  
Density Functional ◽  
Molecular Magnets ◽  
Molecular Magnet ◽  
Transmission Coefficients ◽  
Molecular Spintronics ◽  
Current Voltage ◽  
Spin Polarized ◽  
Characteristic Features

Focusing on the framework of how to realize the molecular spintronics in a single molecular magnet, we present theoretical studies on the spin-polarized quantum transport behavior through a single Mn12 molecular magnet. Our theoretical results were obtained by carrying out density functional theoretical calculation within the Keldysh nonequilibrium Green function formalism. The ultimate goal of the molecular spintronics is to develop single molecule transistors which generate spin-polarized currents through the molecular magnet. We obtained the densityof states, the transmission coefficients and the characteristic features of the current–voltage (I–V) on the spin-polarized transport properties of Mn12 by the theoretical calculation. These results show the possibility for the realization of molecular spintroinics using single molecular magnets.

Spin-Polarized Current of a Transistor in Single Mn12 Molecular Magnets

2007 ◽  
Vol 7 (11) ◽  
pp. 4111-4115 ◽  
Author(s):  
Joonho Park ◽  
Heok Yang ◽  
K.-S. Park ◽  
Eok-Kyun Lee
Keyword(s):  
Theoretical Calculation ◽  
Single Molecule ◽  
Density Functional ◽  
Molecular Magnets ◽  
Molecular Magnet ◽  
Transmission Coefficients ◽  
Molecular Spintronics ◽  
Current Voltage ◽  
Spin Polarized ◽  
Characteristic Features

Focusing on the framework of how to realize the molecular spintronics in a single molecular magnet, we present theoretical studies on the spin-polarized quantum transport behavior through a single Mn12 molecular magnet. Our theoretical results were obtained by carrying out density functional theoretical calculation within the Keldysh nonequilibrium Green function formalism. The ultimate goal of the molecular spintronics is to develop single molecule transistors which generate spin-polarized currents through the molecular magnet. We obtained the densityof states, the transmission coefficients and the characteristic features of the current–voltage (I–V) on the spin-polarized transport properties of Mn12 by the theoretical calculation. These results show the possibility for the realization of molecular spintroinics using single molecular magnets.

scholarly journals Electrical properties and mechanical stability of anchoring groups for single-molecule electronics

2015 ◽  
Vol 6 ◽  
pp. 1558-1567 ◽  
Author(s):  
Riccardo Frisenda ◽  
Simge Tarkuç ◽  
Elena Galán ◽  
Mickael L Perrin ◽  
Rienk Eelkema ◽  
...  
Keyword(s):  
Single Molecule ◽  
Density Functional ◽  
Mechanical Stability ◽  
Phenylene Ethynylene ◽  
Current Voltage ◽  
Single Molecule Electronics ◽  
Level Model ◽  
Anchoring Groups ◽  
Experimental Findings

We report on an experimental investigation of transport through single molecules, trapped between two gold nano-electrodes fabricated with the mechanically controlled break junction (MCBJ) technique. The four molecules studied share the same core structure, namely oligo(phenylene ethynylene) (OPE3), while having different aurophilic anchoring groups: thiol (SAc), methyl sulfide (SMe), pyridyl (Py) and amine (NH2). The focus of this paper is on the combined characterization of the electrical and mechanical properties determined by the anchoring groups. From conductance histograms we find that thiol anchored molecules provide the highest conductance; a single-level model fit to current–voltage characteristics suggests that SAc groups exhibit a higher electronic coupling to the electrodes, together with better level alignment than the other three groups. An analysis of the mechanical stability, recording the lifetime in a self-breaking method, shows that Py and SAc yield the most stable junctions while SMe form short-lived junctions. Density functional theory combined with non-equlibrium Green’s function calculations help in elucidating the experimental findings.

Theory of the Rectifying Performance in Molecular Device: The Role of Anchoring Groups

2011 ◽  
Vol 181-182 ◽  
pp. 344-347 ◽  
Author(s):  
Cai Juan Xia ◽  
Han Chen Liu ◽  
Ying Tang Zhang
Keyword(s):  
Single Molecule ◽  
Electronic Transport ◽  
Density Functional ◽  
Electrical Response ◽  
Molecular Device ◽  
Functional Theory ◽  
Transmission Coefficients ◽  
External Bias ◽  
Anchoring Groups

The electronic transport of the single molecule via different anchoring groups is studied using density functional theory in conjunction with the nonequilibrium Green’s function. The results show that the electronic transport properties are strongly dependent on the anchoring groups. Asymmetric electrical response for opposite biases is observed resulting in significant rectification in current. The transmission coefficients and spatial distributions of molecular orbitals under various external biases voltage are analyzed, and it suggests that the asymmetry of the coupling between the molecule and the electrodes with external bias leads to rectifying performance.

scholarly journals STM Spectroscopy of Star-Type Molecular Magnet

2012 ◽  
Vol 60 (1) ◽  
pp. 87-91
Author(s):  
MS Alam ◽  
FA Chowdhury ◽  
RW Saalfrank ◽  
AV Postnikov ◽  
P Müller
Keyword(s):  
Single Molecule ◽  
Density Functional ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Molecular Magnet ◽  
Large Signal ◽  
Tunneling Microscopy ◽  
Functional Theory ◽  
Metal Centers ◽  
Stm Images

In order to achieve a better understanding of how scanning tunneling microscopy (STM) images of metallo-complexes are related to the geometric and electronic structure, we performed scanning microscopy (STM) and scanning tunneling spectroscopy (STS) techniques on [FeIIIFeIII 3L6] (L= N-methylaminediethanolate) star-type tetranuclear molecular magnet. The experiments were performed under ambient condition. We were able to image single molecule by STM with submolecular resolution. In our STS measurements we found a rather large signal at the positions of iron ion centers in the molecules. This direct addressing of metal centers was further confirmed by density functional theory (DFT) calculations.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10343  Dhaka Univ. J. Sci. 60(1): 87-91 2012 (January)

FIRST-PRINCIPLES STUDY ON PHOTOSWITCHING BEHAVIOR IN SINGLE MOLECULE JUNCTION

2018 ◽  
Vol 25 (03) ◽  
pp. 1850070 ◽  
Author(s):  
BAO-AN BIAN ◽  
YA-PENG ZHENG ◽  
PEI-PEI YUAN ◽  
BIN LIAO ◽  
YU-QIANG DING
Keyword(s):  
Single Molecule ◽  
First Principles ◽  
Density Functional ◽  
Molecular Switch ◽  
Functional Theory ◽  
Current Voltage ◽  
Molecule Junction ◽  
Single Molecule Junction ◽  
Close Form ◽  
Non Equilibrium Green’S Function

We carry out first-principles calculations based on density functional theory and non-equilibrium Green’s function to investigate the electronic transport properties of a diarylethene-based molecule sandwiched between two Au electrodes. This molecular switch can be reversed between open and close forms by using light stimulation. We analyze the switch behavior of these two forms through the current–voltage curves, transmission spectra and molecular projected self-consistent Hamiltonian. It has been found that the current of the close form is significantly larger than the open form, and there is a large and stable switch ratio in a wide bias window. This result indicates that this molecule can become one of the good candidates for optical molecular switch in the future.

Fine Spin Filtering Effect in Co-Phthalocyanine Molecule Induced by the Spin Polarization of Co Atom

2014 ◽  
Vol 597 ◽  
pp. 127-130
Author(s):  
Yan Hong Zhou ◽  
X.H. Qiu ◽  
L.L. Zhou ◽  
Y.L. Peng
Keyword(s):  
Single Molecule ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Underlying Mechanism ◽  
Spintronic Devices ◽  
Spin Direction ◽  
Spin Polarized ◽  
Phthalocyanine Molecule ◽  
Filtering Effect ◽  
Spin Filtering

Spintronic devices will play a very important role in future information technology. In this study, By spin-polarized density-functional theory calculations combined with the Keldysh nonequilibrium Green’s method, the effect of the spin direction of Co atom in Co- phthalocyanine molecule in modulating spin filtering effects under external biases are investigated. Here, an individual single molecule Co-phthalocyanine is sandwiched between two infinite 8-zigzag-graphene nanoribbon electrodes. we find that the spin direction of the Co atom relative to the magnetic polarization of the left and right electrodes can improve the spin filtering effect greatly. when the polarization direction of the two electrodes is antiparallel and the polarization of Co atom in the Co-phthalocyanine molecule upward, the configuration posesses almost perfectly spin-filter effect. The underlying mechanism of the perfect spin filtering action is applied.

scholarly journals Electron and heat transport in porphyrin-based single-molecule transistors with electro-burnt graphene electrodes

2015 ◽  
Vol 6 ◽  
pp. 1413-1420 ◽  
Author(s):  
Hatef Sadeghi ◽  
Sara Sangtarash ◽  
Colin J Lambert
Keyword(s):  
Density Functional Theory ◽  
Single Molecule ◽  
Fermi Energy ◽  
Density Functional ◽  
Function Method ◽  
Voltage Characteristic ◽  
Frontier Orbitals ◽  
Current Voltage Characteristic ◽  
Functional Theory ◽  
Current Voltage

We have studied the charge and thermal transport properties of a porphyrin-based single-molecule transistor with electro-burnt graphene electrodes (EBG) using the nonequilibrium Green’s function method and density functional theory. The porphyrin-based molecule is bound to the EBG electrodes by planar aromatic anchor groups. Due to the efficient π–π overlap between the anchor groups and graphene and the location of frontier orbitals relative to the EBG Fermi energy, we predict HOMO-dominated transport. An on–off ratio as high as 150 is predicted for the device, which could be utilized with small gate voltages in the range of ±0.1 V. A positive thermopower of +280 μV/K is predicted for the device at the theoretical Fermi energy. The sign of the thermopower could be changed by tuning the Fermi energy. By gating the junction and changing the Fermi energy by +10 meV, this can be further enhanced to +475 μV/K. Although the electrodes and molecule are symmetric, the junction itself can be asymmetric due to different binding configurations at the electrodes. This can lead to rectification in the current–voltage characteristic of the junction.

scholarly journals Methods and Models of Theoretical Calculation for Single-Molecule Magnets

2021 ◽  
Vol 7 (8) ◽  
pp. 107
Author(s):  
Qian-Cheng Luo ◽  
Yan-Zhen Zheng
Keyword(s):  
Theoretical Calculation ◽  
Single Molecule ◽  
High Performance ◽  
Density Functional ◽  
Coupling Constants ◽  
Single Molecule Magnets ◽  
Magnetic Exchange ◽  
Functional Theory ◽  
Complete Active Space ◽  
Self Consistent Field

Theoretical calculation plays an important role in the emerging field of single-molecule magnets (SMMs). It can not only explain experimental phenomena but also provide synthetic guidance. This review focuses on discussing the computational methods that have been used in this field in recent years. The most common and effective method is the complete active space self-consistent field (CASSCF) approach, which predicts mononuclear SMM property very well. For bi- and multi-nuclear SMMs, magnetic exchange needs to be considered, and the exchange coupling constants can be obtained by Monte Carlo (MC) simulation, ab initio calculation via the POLY_ANISO program and density functional theory combined with a broken-symmetry (DFT-BS) approach. Further application for these calculation methods to design high performance SMMs is also discussed.

Magnetic Properties of Embedded Rh Clusters in Ni Matrix

1995 ◽  
Vol 384 ◽  
Author(s):  
Zhi-Qiang Li ◽  
Yuichi Hashi ◽  
Jing-Zhi Yu ◽  
Kaoru Ohno ◽  
Yoshiyuki Kawazoe
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Magnetic Moments ◽  
Functional Formalism ◽  
Rhodium Clusters ◽  
Spin Polarized ◽  
Local Density Functional

ABSTRACTThe electronic structure and magnetic properties of rhodium clusters with sizes of 1 - 43 atoms embedded in the nickel host are studied by the first-principles spin-polarized calculations within the local density functional formalism. Single Rh atom in Ni matrix is found to have magnetic moment of 0.45μB. Rh13 and Rhl 9 clusters in Ni matrix have lower magnetic moments compared with the free ones. The most interesting finding is tha.t Rh43 cluster, which is bulk-like nonmagnetic in vacuum, becomes ferromagnetic when embedded in the nickel host.

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