错误的电子铁电和平面带在扭曲的双轴机 Tl2S 的出现
Zhigang Gui1, Wei Li2, Li Huang1,3
1Department of Physics & Academy for Advanced Interdisciplinary Studies, Southern University of Science & Technology, Shenzhen, Guangdong 518055, China.
Nano letters
|February 28, 2024
概括
Tl2S的大角度扭转会产生具有外平面偏振的二维铁电. 这种新的电子铁电与平面带和范霍夫奇点共存,为物理学和材料应用开辟了新的途径.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 材料科学 材料科学 材料科学
- 固态化学 固态化学
背景情况:
- 具有外平面 (OP) 偏振的二维 (2D) 铁电对于先进的电子应用和基本物理研究至关重要.
- 在2D材料中实现OP偏振的现有方法面临局限性.
研究的目的:
- 为了研究层间扭曲在稳定二维材料中平面外偏振的潜力.
- 探索扭曲的双层Tl2S表现出铁电的潜在机制和电子特性.
主要方法:
- 使用第一原则计算来研究扭曲双层Tl2S的结构和电子特性.
- 分析的重点是层间扭曲效应,二极管排序和声模式.
主要成果:
- 大角间层扭曲诱导了Tl2S中稳定的外平面极化,与之前的发现形成鲜明对比.
- 铁电被认为是不恰当的和电子的,源于电子驱动的极性顺序和特定的声模式之间的非线性合.
- 扭曲的双层Tl2S表现出一个平面带和一个范霍夫奇点在费米水平附近.
结论:
- 层间扭曲是一种有效的策略,可以在Tl2S等二维材料中实现非平面铁电.
- 不恰当的电子铁电,平面带和范霍夫奇点的独特组合为新的物理和设备应用提供了令人兴奋的机会.
相关概念视频
Crystal Field Theory - Tetrahedral and Square Planar Complexes
42.5K
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,...
42.5K
Predicting Molecular Geometry
34.3K
VSEPR Theory for Determination of Electron Pair Geometries
34.3K
Fermi Level
598
The Fermi-Dirac function is represented by an S-shaped curve indicating the probability of an energy state being occupied by an electron at a given temperature. The Fermi level is the energy level at which there is a fifty percent chance of finding an electron, and it is positioned between the lower-energy valence band and the higher-energy conduction band.
At absolute zero temperature, electrons fill all energy states up to the Fermi level, leaving upper states empty. As the temperature rises,...
At absolute zero temperature, electrons fill all energy states up to the Fermi level, leaving upper states empty. As the temperature rises,...
598
Dielectric Polarization in a Capacitor
4.7K
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...
4.7K
Fermi Level Dynamics
246
The vacuum level denotes the energy threshold required for an electron to escape from a material surface. It is usually positioned above the conduction band of a semiconductor and acts as a benchmark for comparing electron energies within various materials.
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
246
Electrostatic Boundary Conditions in Dielectrics
1.2K
When an electric field passes from one homogeneous medium to another, crossing the boundary between the two mediums imparts a discontinuity in the electric field. This results in electrostatic boundary conditions that depend on the type of mediums the field propagates through.
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's...
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's...
1.2K


