通过四面体FeSe_{1-x}S_{x}超导体中的乱来提升间隙节点
T Nagashima1, K Ishihara1, K Imamura1
1Department of Advanced Materials Science, <a href="https://ror.org/057zh3y96">University of Tokyo</a>, Kashiwa, Chiba 277-8561, Japan.
Physical review letters
|October 25, 2024
概括
破坏具有缺陷的铁化硫酸的超导状态,揭示了其博戈利乌波夫·费米表面没有拓保护. 这项研究表明,这些异国情调对杂质很敏感,从节点过渡到无节点.
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
- 超导电性 超导电性 超导电性
背景情况:
- 四边形FeSe_{1-x}S_{x}表现出时间逆向对称性破坏和大量残余状态密度,这表明它与博格鲁博夫费米表面 (Bogoliubov Fermi surfaces,简称BFSs) 有着超极管超导状态.
- 理论上预计BFS在中心对称超导体中的拓保护,但它们对杂质的实验反应在很大程度上仍未被探索.
研究的目的:
- 为了研究通过电子辐射引入的受控缺陷对四角形FeSe_{1-x}S_{x} (0.18≤x≤0.25) 的超导状态的影响.
- 在杂质散射下实验性地探测波戈卢布沃夫费米表面的性质和稳定性.
主要方法:
- 电子辐射被用来在原始的FeSe_{1-x}S_{x}样本中引入受控缺陷.
- 测量了磁透深度的温度依赖性,以探测低能刺激.
- 对光谱特征的分析,以确定超导状态中的过渡.
主要成果:
- 原始FeSe_{1-x}S_{x}样本的磁透深度数据与采用BFS的模型一致.
- 电子辐射诱导了低能激发的非单调演变,并增加了杂质度.
- 观察到从节点过渡到无节点超导,最终导致无间隙状态与安德里耶夫结合状态,类似于节点s_{±}情况.
结论:
- 在四面体FeSe_{1-x}S_{x}中,波格卢波夫费米表面似乎是偶然形成的,并且容易因混乱而被破坏.
- 实验结果挑战了在现实条件下在这种材料系统中为BFS提供强大的拓保护的概念.
相关概念视频
02:58Crystal Field Theory - Octahedral Complexes
26.2K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
26.2K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
41.6K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
41.6K
01:31Ferromagnetism
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
01:24Superconductor
1.1K
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...
1.1K
02:54Trends in Lattice Energy: Ion Size and Charge
23.8K
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:
23.8K
01:18Fermi Level
517
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,...
517