和固体的固有不和性是固有的.
Matthias T Agne1, Shashwat Anand1, G Jeffrey Snyder1
1Department Materials Science and Engineering, Northwestern University, Evanston, IL, USA.
Research (Washington, D.C.)
|April 15, 2024
概括
我们证明了原子振动会产生"声子压力",甚至在和固体中也会引起热膨胀. 这一发现将和性质与非和性质联系起来,使新的材料设计指标成为可能.
科学领域:
- 材料科学 材料科学 材料科学
- 固态物理 固态物理
- 热力学是一种热力学.
背景情况:
- 原子振动 (声子) 决定了材料的热行为.
- 的近似模型是线性原子力,而非的相互作用解释了热膨胀和导电性.
- 当前的模型经常将热现象仅归因于不和性.
研究的目的:
- 为了证明原子动能在固体中产生'声子压力',类似于气体压力.
- 为了证明这种声子压力自然会导致热膨胀,即使在波系统中.
- 开发一个对格鲁尼森参数和格子导热率的和估计.
主要方法:
- 模拟原子振动作为一个弹质量系统.
- 介绍了由原子动能产生的"声压"概念.
- 根据声音速度,推导出格鲁尼森参数的和估计.
- 开发一种高通量方法来估计网格导热率.
主要成果:
- 固体中的原子动能会产生取决于温度的"声子压力".
- 这种声子压力本质上会导致热膨胀,这意味着即使在和固体中也存在不和性.
- 一个和格林尼森参数被估计为横向和纵向声速的比率.
- 一种高通量波方法用于格子导热率估计,其结果与最先进的方法相当.
结论:
- 这项研究确立了和性质与非和效应 (如热膨胀) 之间的直接联系.
- 它为理解和性及其起源提供了一个新的理论框架.
- 这些发现为新型材料工程设计指标提供了基础,特别是热性能.
相关概念视频
Modes of Standing Waves - I
2.9K
A close look at earthquakes provides evidence for the conditions appropriate for resonance, standing waves, and constructive and destructive interference. A building may vibrate for several seconds with a driving frequency matching the building's natural frequency of vibration; this produces a resonance that results in one building collapsing while the neighboring buildings do not. Often, buildings of a certain height are devastated, while other taller buildings remain intact. This...
2.9K
Energy Bands in Solids
849
Isolated atoms have discrete energy levels that are well described by the Bohr model. And, it quantifies the energy of an electron in a hydrogen atom as En. Higher quantum numbers 'n' yield less negative, closer electron energy levels.
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...
849
Structures of Solids
14.1K
Solids in which the atoms, ions, or molecules are arranged in a definite repeating pattern are known as crystalline solids. Metals and ionic compounds typically form ordered, crystalline solids. A crystalline solid has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy. Amorphous solids or non-crystalline solids (or, sometimes, glasses) which lack an ordered internal structure and are randomly arranged. Substances that...
14.1K
Harmonic Mean
3.1K
The arithmetic mean is usually skewed towards the larger values in the data set. Therefore, to avoid this inherent bias towards smaller values, the harmonic mean is used.
Take the example of the speed of a car, which is the measure of the rate of distance traveled. If the vehicle traverses the same distance back-and-forth, its average speed equals the total distance traveled divided by the total time taken. However, if the car moves with varying speeds, then the arithmetic mean is more skewed...
Take the example of the speed of a car, which is the measure of the rate of distance traveled. If the vehicle traverses the same distance back-and-forth, its average speed equals the total distance traveled divided by the total time taken. However, if the car moves with varying speeds, then the arithmetic mean is more skewed...
3.1K
Molecular and Ionic Solids
17.1K
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...
17.1K
Resonance and Hybrid Structures
16.9K
According to the theory of resonance, if two or more Lewis structures with the same arrangement of atoms can be written for a molecule, ion, or radical, the actual distribution of electrons is an average of that shown by the various Lewis structures.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
16.9K


