链中的金属绝缘器过渡与相关的障碍
Pedro Carpena1, Pedro Bernaola-Galván, Plamen Ch Ivanov
1Departamento de Física Aplicada II, ETSI de Telecomunicación, Universidad de Málaga, 29071 Málaga, Spain. pcarpena@ctima.uma.es
Nature
|August 29, 2002
概括
在混乱中引入远程相关性可以诱导一维固体中的金属绝缘体过渡. 这种过渡,以一个临界指数值为特征,决定了系统是否作为导体或绝缘体.
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
- 量子力学就是量子力学.
背景情况:
- 布洛赫定理描述了有序晶体中扩展的电子波函数,导致金属行为.
- 晶体中的障碍可以导致电子定位和金属绝缘体过渡 (安德森过渡).
- 一维二进制固体及其电子特性具有显著的兴趣.
研究的目的:
- 理论上研究长距离相关失调对1D二进制固体中电子波函数的影响.
- 为了识别相关联诱导的金属绝缘体过渡及其特征.
- 探索这些发现对DNA中电子传输的相关性.
主要方法:
- 电子波函数的理论研究.
- 使用一维紧固结合模型进行数值模拟.
- 分析一个关键指数,描述长距离的相关性.
主要成果:
- 确定了一种由相关性诱导的金属绝缘体过渡.
- 确定了相关指数的值.
- 在值以上,系统表现出金属行为;在此值以下,则表现出绝缘行为.
结论:
- 混乱中的远程相关性可以从根本上改变1D固体的电子特性.
- 这些发现表明,在像DNA这样的系统中,导电性存在一种机制.
- 这项研究提供了对相关无序系统中安德森过渡的见解.
相关概念视频
Trends in Lattice Energy: Ion Size and Charge
An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure of the strength of this attraction. The lattice energy (ΔHlattice) of an ionic compound is defined as the energy required to separate one mole of the solid into its component gaseous ions. For the ionic solid sodium chloride, the lattice energy is the enthalpy change of the process:
Bonding in Metals
Metallic bonds are formed between two metal atoms. A simplified model to describe metallic bonding has been developed by Paul Drüde called the “Electron Sea Model”.
Metallic Solids
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
Band Theory
When two or more atoms come together to form a molecule, their atomic orbitals combine and molecular orbitals of distinct energies result. In a solid, there are a large number of atoms, and therefore a large number of atomic orbitals that may be combined into molecular orbitals. These groups of molecular orbitals are so closely placed together to form continuous regions of energies, known as the bands.
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
Properties of Transition Metals
Transition metals are defined as those elements that have partially filled d orbitals. As shown in Figure 1, the d-block elements in groups 3–12 are transition elements. The f-block elements, also called inner transition metals (the lanthanides and actinides), also meet this criterion because the d orbital is partially occupied before the f orbitals.
Theory of Metallic Conduction
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,...


