オーガニック分子金属における超伝導性の変動は,Mott 移行に近い
Moon-Sun Nam1, Arzhang Ardavan, Stephen J Blundell
1Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU, UK.
Nature
|October 5, 2007
まとめ
非常識な超伝導体では,移行温度以上の変動する超伝導性は,モット絶縁状態に近い状態から生じることがあります. 有機分子金属で観察されるこの現象は,Coulomb相関の増大と関連しています.
科学分野:
- 凝縮物質物理学 凝縮物質物理学
- マテリアルサイエンス 材料科学
- オーガニック・エレクトロニクス
背景:
- 従来の超伝導体は,クーパーペアリングと,臨界温度 (T (c)) 以下の冷却時にエネルギーギャップを示します.
- 非常識な超伝導体は,T (c) 以上の"擬似ギャップ現象"を示し,ギャップ形成は超流動性から切り離されます.
- 強い電子対電子相互作用 (クーロン反発U) を特徴とするモットの絶縁状態は,電子特性に影響する.
研究 の 目的:
- 非従来の超伝導体におけるMott絶縁状態と変動する超伝導性の関連性を調査する.
- クーロン相関が偽ギャップ現象にどのように影響するかを探求する.
- 電子状態のチューニングにおけるt/Uパラメータの役割を理解する.
主な方法:
- kappa-(BEDT-TTF) 2X有機分子金属システムを使用し,t/U比で調節可能でした.
- 超伝導体の変動を感知する探査機として渦 - ネルスト効果を使用した.
- t/U.の減少の関数として変動レジムの発展を分析した.
主要な成果:
- 波動的な超伝導性は,移行温度より大幅に上方に発達することが観察されました.
- これらの変動の発生は,t/U比の減少と相関していた.
- クーロンブ相関 (U) の影響の増大は,波動の増大と関連していた.
結論:
- Mott 絶縁状態の接近は,非従来の超伝導体における変動する超伝導性を誘導する可能性があります.
- クーロン相関は,偽ギャップ現象の出現において重要な役割を果たします.
- t/Uパラメータは,金属と絶縁の間のバランスを効果的に調整し,超伝導体の変動に影響を与えます.
さらに関連する動画
04:51Comparison of Two Different Synthesis Methods of Single Crystals of Superconducting Uranium Ditelluride
Published on: July 8, 2021
2.7K
06:53Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
2.5K
関連する概念動画
Bonding in Metals
45.6K
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”.
45.6K
Properties of Transition Metals
28.2K
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.
28.2K
Superconductor
1.9K
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...
1.9K
Types Of Superconductors
1.7K
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...
1.7K
Ferromagnetism
2.8K
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...
2.8K
Theory of Metallic Conduction
2.0K
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,...
2.0K
