二级恩-泰勒效应在二维NbO2X (X = I, Br) 中诱导了高温铁电
Huasheng Sun1, Kaiming Deng1, Erjun Kan1
1MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing, and Department of Applied Physics, Nanjing University of Science and Technology Nanjing 210094 People's Republic of China njustdyp@njust.edu.cn ekan@njust.edu.cn.
Nanoscale advances
|June 1, 2023
概括
二维 (2D) 材料NbO2I和NbO2Br具有稳定的铁电特性. 这些新型材料显示出下一代电子设备的潜力,因为它们的基里温度很高.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 固态化学 固态化学
背景情况:
- 二维 (2D) 材料具有独特的电子和物理性能.
- 探索新的二维材料对于推进电子设备技术至关重要.
- 铁电材料对于非挥发性内存和其他应用是必不可少的.
研究的目的:
- 为了研究二维 (2D) 材料NbO2I和NbO2Br的铁电特性.
- 评估这些新型二维铁电材料的稳定性和潜在应用.
主要方法:
- 用第一原理计算来研究铁电性质.
- 使用裂隙能量分析,声子频谱和分子动力学模拟来确认稳定性.
- 总能量计算和蒙特卡洛模拟确定了铁电极化和库里温度.
- 轨道选择性外部电位方法确定了铁电的起源.
主要成果:
- 单层NbO2I和NbO2Br具有动态和热稳定性.
- 铁电相是NbO2I和NbO2Br单层的基本状态.
- 在平面内计算的铁电极化为NbO2I的384.5 pC/m,为NbO2Br的375.2 pC/m.
- 预测了高的内在基里温度:NbO2I的1700K和NbO2Br的1500K.
- 二级的Jahn-Teller效应被确定为铁电的起源.
结论:
- 单层NbO2I和NbO2Br是动态和热稳定的二维铁电材料.
- 这些材料具有显著的铁电极化和高基里温度,使它们适合应用.
- 铁电的确定的起源为设计未来的铁电材料提供了基本的见解.
相关概念视频
01:31Ferromagnetism
2.4K
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
2.4K
02:54Molecular and Ionic Solids
17.3K
Crystalline solids are divided into four types: molecular, ionic, metallic, and covalent network based on the type of constituent units and their interparticle interactions.
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
17.3K
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
1.1K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.1K
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
1.1K
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...
1.1K
02:58Crystal Field Theory - Octahedral Complexes
26.9K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
26.9K
01:08Spin–Spin Coupling Constant: Overview
964
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...
964