混合价值磁二极体中的分子自旋电子学:双交换封锁机制
Alessandro Soncini1, Talal Mallah, Liviu F Chibotaru
1Institute for Nanoscale Physics and Chemistry (INPAC) and Division of Quantum and Physical Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium. Alessandro.Soncini@chem.kuleuven.be
Journal of the American Chemical Society
|May 25, 2010
概括
铁复合体中的旋转移位可能会由于反铁磁合阻断电荷传输,这与直觉相反. 这种"双交换封锁"机制影响了自旋传输,与铁磁二极管不同.
科学领域:
- 量子化学 是一个量子化学.
- 分子电子学分子电子学
- 这就是Spintronics.
背景情况:
- 研究分子系统中的电荷和自旋传输对于开发先进的电子设备至关重要.
- 双核铁复合体具有可调节的磁性和电子性质,使其成为分子自旋电子学的有希望的候选者.
- 了解电子移位,磁性合和传输现象之间的相互作用是控制分子导电性的关键.
研究的目的:
- 从理论上研究通过连接到金属电极的双核Fe(III) Fe(III) 铁复合体的电荷和自旋传输.
- 阐明电子移位和磁性合在决定库伦堡封锁制度下的传输特性中的作用.
- 探索观察到的运输行为背后的机制及其与旋转角运动量保护的关系.
主要方法:
- 理论研究电荷和自旋传输现象.
- 对一个双核Fe(III) Fe(III) 二次体进行分析,该二次体经历一个电子的减少,达到混合价值Fe(II) Fe(III) 状态.
- 数字模拟包括振动合效应.
主要成果:
- 反铁磁合的Fe (III) Fe (III) 二次体中增加的电子偏位导致电荷传输的阻塞,这与直观的预期相反.
- 这种运输封锁归因于"双交换封锁"机制,违反了旋转角动量守恒.
- 铁磁合的二极管不受这种阻塞的影响,而振动式合增强了混合度二极管中的旋转电流与移位.
结论:
- 旋转移位和反铁磁合之间的相互作用可以阻碍分子系统中的电荷传输.
- 双交换封锁机制为混合价值分子二次体中的自旋依赖运输提供了新的视角.
- 结果为设计具有控制自旋传输特性的分子电子元件提供了洞察力.
更多相关视频
06:53Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
11:33All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
Published on: January 19, 2018
相关概念视频
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
03:02Colors and Magnetism
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
01:26Diamagnetism
Materials consisting of paired electrons have zero net magnetic moments. However, when these materials are placed under an external magnetic field, the moments opposite to the field are induced. Such materials are called diamagnets. Diamagnetism is the response of the diamagnets when placed in an external magnetic field.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets.
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
01:14Diamagnetic Shielding of Nuclei: Local Diamagnetic Current
An applied magnetic field causes the electrons present in the molecule to circulate, setting up a local diamagnetic current within the molecule. The local diamagnetic current arising from circulating sigma-bonding electrons induces a magnetic field, Blocal that opposes the applied magnetic field, B0. The effective magnetic field experienced by these nuclei is given by the difference between the applied and local magnetic fields in a phenomenon called local diamagnetic shielding. Essentially,...
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...