Lanthanide Organometallic Sandwich Nanowires:  Formation Mechanism

Hosoya, Natsuki; Takegami, Ryuta; Suzumura, Jun Ichi; Yada, Keizo; Koyasu, Kiichirou; Miyajima, Ken; Mitsui, Masaaki; Knickelbein, Mark B.; Yabushita, Satoshi; Nakajima, Atsushi

doi:10.1021/jp0452103

Cited by 80 publications

(87 citation statements)

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“…Our calculations confirm that the structures of the Eu 2 C 8 H 8 3 molecule and its ionic species are sandwiches with the metal atom above the center of gravity of C 8 H 8 ligand molecules [8][9][10] anion for which the energy difference between FM and AFM magnetic states vanishes.…”

supporting

confidence: 68%

“…Because of the strong aromatic character [19,20] of the orbitals located at the C 8 H 8 rings the 4f electrons are drastically shifted in energy from the low part of the valence electrons towards the Fermi level [which is placed in the middle of the highest occupied molecular orbital -lowest unoccupied molecular orbital (HOMO-LUMO) gap]. This effect has been also observed in the experiments [8,10]. The new molecular orbitals, formed in a similar manner as previously shown for other sandwich-type systems (see [17] and the references therein), accommodate the 6s as well as small fractions of 4f electrons of the Eu atoms.…”

mentioning

confidence: 64%

“…The charge-difference plots of the molecule against the sum of the separated systems, Eu 2 and C 8 H 8 3 , together with the analysis of the charge transfer in or out of the pseudopotential spheres confirm a strong ionic character of the bonding between Eu and C 8 H 8 ligands [8][9][10]18]. The Eu 6s electrons are transferred to an aromatic type molecular orbital characterized by a high density of states of the C sites; therefore, the Eu atom can formally be seen as a 2 positive ion [10].…”

mentioning

confidence: 74%

“…In order to take into account the proper orbital dependence of the Coulomb and exchange interaction we employed the LDA U method in treating the Eu 4f states [15], which improves not only the description of the ground state properties such as magnetic moments and interatomic exchange parameters, but also excited states and energy gaps [15,16]. The photoelectron spectra for the Eu n C 8 H 8 ÿ1 n1 n 1-7 sandwiches show a photodetachment contribution of 4f orbitals between 3.0 -4.0 eV [8,10]. More precisely, a value of 3.7 eV corresponds to the photodetachment energy in one-end double sandwich anion Eu 2 C 8 H 8 1ÿ 2 [10].…”

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confidence: 99%

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Controlling the Magnetization Direction in Molecules via Their Oxidation State

et al. 2008

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By means of ab initio calculations we predict that it is possible to manipulate the magnetization direction in organic magnetic molecules by changing their oxidation state. We demonstrate this novel effect on the Eu 2 C 8 H 8 3 molecule, in which the hybridization of the outer ring states with the Eu 4f states causes a redistribution of the orbitals around the Fermi level leading to a strong ferromagnetism due to a hole-mediated exchange mechanism. As a key result, we predict an oscillatory behavior of the easy axis of the magnetization as a function of the oxidation state of the molecule -a new effect, which could lead to new technological applications. DOI: 10.1103/PhysRevLett.100.117207 PACS numbers: 75.75.+a, 75.50.Xx, 85.35.Gv, 85.65.+h The miniaturization of the structures used in modern ultra-high-density magnetic recording aims at nonvolatility, low-energy consumption, and short access times for reading and writing. The nanostructured layered inorganic magnetic materials will reach soon the limit of nanopatterning [1], which motivates the search for completely new approaches. In this respect, organic molecular magnets are very promising candidates as working units for spintronics [2 -4]. From the technological functionality point of view, besides a small size, they are required to have a strong ferromagnetic coupling of local spin moments and large values of magnetic anisotropy energy (MAE), a quantity crucial for practical applications. MAE gives an estimate for the energy barrier necessary to stabilize the magnetic moments against quantum tunneling and thermal fluctuations.However, an easy way to control the spin polarized electrons in downscaling devices has proved to be quite a challenge. In particular, the effective ways of dynamical control of the magnetization direction in small magnetic bits used for storage and transport applications are still to be established. Because of the reduced dimensions, for the high-temperature applications the magnetic bits have to exhibit huge values of magnetic anisotropy to resist the temperature fluctuations. Moreover, controlling the magnetization direction, electronic and transport properties of the bits have to be easily manageable and should avoid applying enormous external magnetic fields due to huge anisotropies [5]. At the moment, temporary solutions of this problem lie in the heat-assisted magnetic recording [6] and in the writing assisted by microwave excitation [7]. But even in such promising techniques the presence of the magnetic field is necessary.In this Letter we propose a simple way to control the magnetization direction in organic magnetic molecules via a basic mechanism, which is common for the biomolecular world: an oxidation-reduction reaction. The transfer of electrons in or out of the molecule, the heart of an oxidation-reduction process, normally modifies not only the electronic properties of the molecule, but can also influence its magnetism drastically. Here we demonstrate that for a special class of ferromagnetic organic molecules the...

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confidence: 68%

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confidence: 64%

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confidence: 74%

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Controlling the Magnetization Direction in Molecules via Their Oxidation State

et al. 2008

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“…Actually, very recently, Hosoya et al have reported the synthesis of Eu-COT nanowires by laser vaporisation techniques. [18] Extension to longer wires incorporating more Th(C 6 H 6 ) units is also expected to result in singlet multiplicity molecules with ten-pelectron benzene fragments. A molecular wire with an adjustable length incorporating high-electron-density C 6 H 6 units is therefore within reach.…”

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confidence: 99%

High‐Electron‐Density C₆H₆ Units: Stable Ten‐π‐Electron Benzene Complexes

Diefenbach¹,

Schwarz²

2005

Chemistry A European J

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The first stable benzene molecule with ten pi electrons is predicted. Stability is achieved through barium atoms acting as an electron-donating "matrix" to C6H6 in the inverted sandwich complex [Ba2(C6H6)]. The bis(barium)benzene complex has been computed at the density functional level of theory by using the hybrid functional mPW1PW91. Ab initio calculations were performed by using the coupled-cluster expansion, CCSD(T). Nucleus independent chemical shift (NICS) indices imply distinct aromatic character in the benzene ring of bis(barium)benzene. The D6h-symmetric structure with a 1A(1g) electronic ground state represents a thermochemically stable, aromatic benzene molecule with four excess pi electrons, stabilised by two barium ions. A possible molecular wire, built up from Ba end-capped thorium-benzene "sandwiches", is discussed.

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Synthetic Hilbert Space Engineering of Molecular Qudits: Isotopologue Chemistry

Wernsdorfer

Rüben

2019

Advanced Materials

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One of the most ambitious technological goals is the development of devices working under the laws of quantum mechanics. Among others, an important challenge to be resolved on the way to such breakthrough technology concerns the scalability of the available Hilbert space. Recently, proof‐of‐principle experiments were reported, in which the implementation of quantum algorithms (the Grover's search algorithm, iSWAP‐gate, etc.) in a single‐molecule nuclear spin qudit (with d = 4) known as 159TbPc2 was described, where the nuclear spins of lanthanides are used as a quantum register to execute simple quantum algorithms. In this progress report, the goal of linear and exponential up‐scalability of the available Hilbert space expressed by the qudit‐dimension “d” is addressed by synthesizing lanthanide metal complexes as quantum computing hardware. The synthesis of multinuclear large‐Hilbert‐space complexes has to be carried out under strict control of the nuclear spin degree of freedom leading to isotopologues, whereby electronic coupling between several nuclear spin units will exponentially extend the Hilbert space available for quantum information processing. Thus, improved multilevel spin qudits can be achieved that exhibit an exponentially scalable Hilbert space to enable high‐performance quantum computing and information storage.

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Lanthanide Organometallic Sandwich Nanowires: Formation Mechanism

Cited by 80 publications

References 7 publications

Controlling the Magnetization Direction in Molecules via Their Oxidation State

Controlling the Magnetization Direction in Molecules via Their Oxidation State

High‐Electron‐Density C₆H₆ Units: Stable Ten‐π‐Electron Benzene Complexes

Synthetic Hilbert Space Engineering of Molecular Qudits: Isotopologue Chemistry

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Lanthanide Organometallic Sandwich Nanowires: Formation Mechanism

Cited by 80 publications

References 7 publications

Controlling the Magnetization Direction in Molecules via Their Oxidation State

Controlling the Magnetization Direction in Molecules via Their Oxidation State

High‐Electron‐Density C6H6 Units: Stable Ten‐π‐Electron Benzene Complexes

Synthetic Hilbert Space Engineering of Molecular Qudits: Isotopologue Chemistry

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Product

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High‐Electron‐Density C₆H₆ Units: Stable Ten‐π‐Electron Benzene Complexes