相关实验视频
Updated: Jun 19, 2025
15:47
Nanofabrication of Gate-defined GaAs/AlGaAs Lateral Quantum Dots
Published on: November 1, 2013
16.2K
在双层石墨烯双量子点中进行三载体旋转封锁和合
Chuyao Tong1, Florian Ginzel2, Annika Kurzmann1,3
1Solid State Physics Laboratory, <a href="https://ror.org/05a28rw58">ETH Zurich</a>, CH-8093 Zurich, Switzerland.
Physical review letters
|July 23, 2024
概括
了解双层石墨烯量子点中的自旋动力学是关键. 研究人员研究了旋转封锁现象,揭示了由磁场和相互作用影响的旋转混合机制的见解.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 量子信息科学是一种量子信息科学.
- 这就是Spintronics.
背景情况:
- 旋转自由度是凝聚物质系统的基础.
- 旋转混合机制对于控制旋转量子比特和理解材料特性至关重要.
- 双叶石墨烯量子点具有较长的自旋-放松时间 (T1高达50毫秒) 与磁场依赖.
研究的目的:
- 在 (1,2) (0,3) 电荷配置的双层石墨烯量子点中研究自旋阻塞现象.
- 检查点间道合和外部磁场方向对旋转阻塞泄漏电流的影响.
- 阐明这些系统中潜在的旋转混合机制.
主要方法:
- 电静态定义的双层石墨烯量子点的制造和表征.
- 测量自旋阻塞泄漏电流作为点间道合的函数.
- 应用磁场的大小和方向的系统变化 (在平面内和平面外).
主要成果:
- 观察到平面外磁场的零场电流峰值,可能是由于共道,侧面峰值表明额外的旋转和谷混合.
- 检测到平面内磁场的零场电流下降,归因于旋转泽曼效应和凯恩-梅尔旋转轨道相互作用之间的竞争.
- 当前潜水的线形分析表明了进一步复杂的机制的参与.
结论:
- 双层石墨烯量子点中的自旋阻塞现象对磁场方向和合强度敏感.
- 多种旋转混合机制,包括旋转轨道相互作用,有助于观察到的运输特征.
- 需要进一步的研究,以充分理解复杂的旋转动态,并确定所有有助于机制.
相关概念视频
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
993
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...
993
01:22Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
1.1K
Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the...
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the...
1.1K
01:08Spin–Spin Coupling Constant: Overview
904
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
904
01:04¹³C NMR: ¹H–¹³C Decoupling
1.1K
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
1.1K
01:17Spin–Spin Coupling: One-Bond Coupling
953
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
953
01:27¹H NMR: Long-Range Coupling
1.7K
The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
1.7K