过渡金属二甲基化物的未扭曲异构体中的铁电
Lukas Rogée1, Lvjin Wang2, Yi Zhang1
1Department of Applied Physics, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, P. R. China.
概括
超薄的铁电和压电装置由新的二硫化/二硫化 (MoS2/WS2) 异构体启用. 这些材料具有显著的外平面特性,为先进的电子应用铺平了道路.
科学领域:
- 材料科学
- 凝聚物质物理学
- 纳米技术
背景情况:
- 二维 (2D) 材料对于下一代电子产品至关重要.
- 超薄器件的铁电和压电性能非常重要.
- 现有的二维材料往往缺乏强大的OOP铁电和压电反应.
研究的目的:
- 研究MoS2/WS2对OOP铁电和压电的潜力.
- 通过可扩展的方法来证明这些异构体的合成.
- 描述它们的压电特性和设备性能.
主要方法:
- 可扩展的一步化学蒸汽沉积 (CVD) 用于合成表层MoS2/WS2异构体.
- 测量平面外的压电常数 (d33).
- 铁电道结 (FTJ) 装置的制造和表征
- 密度函数理论 (DFT) 的计算.
主要成果:
- 在未扭曲,相称的MoS2/WS2异构体中证明了意想不到的OOP铁电和压电.
- 达到1.952.09pm/V的d33压电常数,大约是单层In2Se3的六倍.
- 通过切换偏振来展示FTJ设备中道电流的三级调节.
- DFT证实,对称性破坏和层间滑动是这些特性的关键.
结论:
- 没有扭曲的,相应的MoS2/WS2异构体是超薄铁和压电子器件的有希望的候选者.
- 可扩展的CVD合成使这些材料的实际制造成为可能.
- 观察到的OOP铁电和压电效应为新的电子功能开辟了新的途径.
相关概念视频
Crystal Field Theory - Tetrahedral and Square Planar Complexes
44.8K
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,...
44.8K
Crystal Field Theory - Octahedral Complexes
28.0K
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...
28.0K
Biasing of Metal-Semiconductor Junctions
345
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
345
Valence Bond Theory
9.7K
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...
9.7K
Ferromagnetism
2.5K
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...
2.5K
Dielectric Polarization in a Capacitor
5.1K
The presence of a dielectric medium in a capacitor not only changes the voltage and capacitance but also affects the electric field. In general, dielectrics can be of two types: polar and nonpolar. In a polar dielectric, the positive and negative charges in the molecules are separated by a distance and hence have a permanent dipole moment. In contrast, no such charge separation exists in a nonpolar dielectric, however the nonpolar molecules get polarized in the presence of an external electric...
5.1K


