在二维铁磁铁Fe3GeTe2中,热导电的温度和厚度依赖
Marcel S Claro1, Javier Corral-Sertal1, Adolfo Otero Fumega2
1CiQUS Centro Singular de Investigacion en Quimica Bioloxica e Materiais Moleculares, Departamento de Quimica-Fisica, Universidade de Santiago de Compostela, Santiago de Compostela E-15782, Spain.
ACS applied materials & interfaces
|October 17, 2023
概括
这项研究探讨了Fe3GeTe2.2等二维铁磁体的导热性. 研究人员发现,由于变化的声子行为,铁磁阶段的导热率下降.
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
- 纳米技术纳米技术
背景情况:
- 范德瓦尔斯材料由于薄弱的层间粘合和破坏对称的顺序而表现出独特的特性.
- 在二维 (2D) 材料中的铁磁性为新的异构结构和可调节的传输特性提供了机会.
研究的目的:
- 通过实验和理论研究二维范德瓦尔斯铁磁体Fe3GeTe2.2的横平面导热率 (κ).
- 了解这种材料中磁相转换和热传输之间的关系.
主要方法:
- 作为厚度的函数,对横平面导热率 (κ) 的实验测量.
- 使用声子特性,理论分析累积的导热率.
- 声组速度和声对声散射速率的计算.
主要成果:
- 观察到 κ 随着厚度的增加而增加,这表明具有弹道贡献的扩散式运输模式.
- 确定了具有10至200 nm之间的平均自由路径的声子的显著贡献.
- 测量了磁过渡时铁磁相中 κ 的减少.
结论:
- κ的减少与声波组速度的降低和磁相中声波-声波散射的增加有关.
- 像Fe3GeTe2这样的范德瓦尔斯铁磁体显示了工程热传输性能的潜力.
- 这项研究突出了2D材料中磁性和声子动态之间的相互作用.
相关概念视频
Ferromagnetism
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
Fermi Level
630
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,...
630
Magnetic Susceptibility and Permeability
1.1K
In linear magnetic materials, like paramagnets and diamagnets, magnetization is proportional to the magnetic field intensity. The constant of proportionality, a dimensionless number, is called magnetic susceptibility. The value of the susceptibility depends on the type of material.
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
1.1K
Theory of Metallic Conduction
1.3K
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
1.3K
Fermi Level Dynamics
258
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...
258
Paramagnetism
2.5K
Paramagnets are materials with unpaired electrons that possess a finite magnetic moment. In the absence of a magnetic field, these moments are randomly oriented, and thus the net moment is zero. Under an external field, a torque acting on the moments tends to align them along the field's direction. However, the random thermal motion of electrons produces a torque opposite to the external field and tries to disorient the moments. These two competing effects align only a few moments along the...
2.5K


