在双层分子超导体中提高了临界温度
John A Schlueter1, Leonore Wiehl, Hyunsoo Park
1Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States. JASchlueter@anl.gov
Journal of the American Chemical Society
|November 3, 2010
概括
研究人员发现了一种具有双包装图案的新型分子超导体,可以达到显著更高的临界温度 (T (c)). 这一发现推动了先进超导材料的开发.
科学领域:
- 材料科学 材料科学 材料科学
- 固态物理 固态物理
- 化学 化学 化学
背景情况:
- 分子超导体为先进的应用提供可调节的特性.
- 控制分子包装对于优化超导的临界温度 (T) 至关重要.
- 之前的研究重点是基于 (BEDT-TTF) 的超导体中的单个包装图案.
研究的目的:
- 研究一种新型分子超导体的晶体结构和超导特性.
- 了解双重包装图案对临界温度 (T) 的影响.
- 为了比较双动图超导体与单动图多态超导体的性能.
主要方法:
- 使用单晶X射线衍射来确定晶体结构.
- 测量了临界温度 (T ((c)) 以评估超导特性.
- 结构分析的重点是识别和表征BEDT-TTF基离子的包装图案.
主要成果:
- 发现 (BEDT-TTF) 的高T(c) 阶段 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TTF) 的 (BEDT-TT) 的 (BEDT-TT) 的) 的 (BEDT-TT-TT-TT-TT-TT-TT-TT-TT-TT-TT-TT-TT-TT-TT).
- 这种双动图结构的临界温度 (T (c)) 是 κ 型多态结构的五倍.
- 存在的 κ-和 α'-类型的包装显著提高了超导性能.
结论:
- 双BEDT-TTF包装图案是实现高临界温度超导的关键.
- 这一发现为设计高性能分子超导体开辟了新的途径.
- 这些发现为我们更深入地了解了分子材料中的结构性质关系.
相关概念视频
Superconductor
A substance that reaches superconductivity, a state in which magnetic fields cannot penetrate, and there is no electrical resistance, is referred to as a superconductor. In 1911, Heike Kamerlingh Onnes of Leiden University, a Dutch physicist, observed a relation between the temperature and the resistance of the element mercury. The mercury sample was then cooled in liquid helium to study the linear dependence of resistance on temperature. It was observed that, as the temperature decreased, the...
Types Of Superconductors
A superconductor is a substance that offers zero resistance to the electric current when it drops below a critical temperature. Zero resistance is not the only interesting phenomenon as materials reach their transition temperatures. A second effect is the exclusion of magnetic fields. This is known as the Meissner effect. A light, permanent magnet placed over a superconducting sample will levitate in a stable position above the superconductor. High-speed trains that levitate on strong...
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,...
Phase Transitions: Melting and Freezing
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
Mechanisms of Heat Transfer II
In convection, thermal energy is carried by the large-scale flow of matter. Ocean currents and large-scale atmospheric circulation, which result from the buoyancy of warm air and water, transfer hot air from the tropics toward the poles and cold air from the poles toward the tropics. The Earth’s rotation interacts with those flows, causing the observed eastward flow of air in the temperate zones. Convection dominates heat transfer by air, and the amount of available space for the airflow...
Ferromagnetism
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...


