scholarly journals How Is the Zero-Resistance of the Superconductor Generated and Is the Phase Diagram of the High-Temperature Superconductivity Explained

2014 ◽  
Vol 03 (02) ◽  
pp. 5-21
Author(s):  
秀园 胡
2013 ◽  
Vol 12 (7) ◽  
pp. 605-610 ◽  
Author(s):  
Shaolong He ◽  
Junfeng He ◽  
Wenhao Zhang ◽  
Lin Zhao ◽  
Defa Liu ◽  
...  

2020 ◽  
Vol 34 (19n20) ◽  
pp. 2040046
Author(s):  
T. Yanagisawa ◽  
M. Miyazaki ◽  
K. Yamaji

It is important to understand the phase diagram of electronic states in the CuO2 plane to clarify the mechanism of high-temperature superconductivity. We investigate the ground state of electronic models with strong correlation by employing the optimization variational Monte Carlo method. We consider the two-dimensional Hubbard model as well as the three-band [Formula: see text]–[Formula: see text] model. We use the improved wave function that takes account of inter-site electron correlation to go beyond the Gutzwiller wave function. The ground state energy is lowered considerably, which now gives the best estimate of the ground state energy for the two-dimensional Hubbard model. The many-body effect plays an important role as an origin of spin correlation and superconductivity in correlated electron systems. We investigate the competition between the antiferromagnetic state and superconducting state by varying the Coulomb repulsion [Formula: see text], the band parameter [Formula: see text] and the electron density [Formula: see text] for the Hubbard model. We show phase diagrams that include superconducting and antiferromagnetic phases. We expect that high-temperature superconductivity occurs near the boundary between antiferromagnetic phase and superconducting one. Since the three-band [Formula: see text]–[Formula: see text] model contains many-band parameters, high-temperature superconductivity may be more likely to occur in the [Formula: see text]–[Formula: see text] model than in single-band models.


2008 ◽  
Vol 7 (12) ◽  
pp. 953-959 ◽  
Author(s):  
Jun Zhao ◽  
Q. Huang ◽  
Clarina de la Cruz ◽  
Shiliang Li ◽  
J. W. Lynn ◽  
...  

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Shoutao Zhang ◽  
Yanchao Wang ◽  
Jurong Zhang ◽  
Hanyu Liu ◽  
Xin Zhong ◽  
...  

2016 ◽  
Vol 852 ◽  
pp. 443-448 ◽  
Author(s):  
Xin Yu Ye ◽  
Qin Li ◽  
Yang Luo ◽  
Di Wu

Only one intermediate compound Ba3Lu4O9was identified at 1373, 1573 and 1773K in the BaO-Lu2O3system in present work.Based on the available experimental phase diagram and relevant thermodynamic data, BaO-Lu2O3 binary system was optimized and calculated by using CALPHAD method. The Gibbs free energy of high temperature solution was described by an ionic two-sublattice model as (Ba2+,Lu3+)P(O2-)Q. The calculated phase diagram, Gibbs energy of intermediate phase Ba3Lu4O9and Gibbs energy of mixingagreewell with experimental resultswithin error limits. The study will offer theoretical basis for further research of the phosphor matrix system of BaO-Lu2O3-SiO2, but also provide new idea for the phase diagram and thermodynamic research on related metallurgical slags, refractories, high-temperature superconductivity material systems.


2019 ◽  
Vol 6 (4) ◽  
pp. 713-718 ◽  
Author(s):  
Xiaoli Huang ◽  
Xin Wang ◽  
Defang Duan ◽  
Bertil Sundqvist ◽  
Xin Li ◽  
...  

ABSTRACT The search for high-temperature superconductivity is one of the research frontiers in physics. In the sulfur hydride system, an extremely high Tc (∼200 K) has been recently developed at pressure. However, the Meissner effect measurement above megabar pressures is still a great challenge. Here, we report the superconductivity identification of sulfur hydride at pressure, employing an in situ alternating-current magnetic susceptibility technique. We determine the superconducting phase diagram, finding that superconductivity suddenly appears at 117 GPa and Tc reaches 183 K at 149 GPa before decreasing monotonically with increasing pressure. By means of theoretical calculations, we elucidate the variation of Tc in the low-pressure region in terms of the changing stoichiometry of sulfur hydride and the further decrease in Tc owing to a drop in the electron–phonon interaction parameter λ. This work provides a new insight into clarifying superconducting phenomena and anchoring the superconducting phase diagram in the hydrides.


2002 ◽  
Vol 16 (20n22) ◽  
pp. 3197-3197
Author(s):  
B. LAKE ◽  
T. E. MASON ◽  
G. AEPPLI ◽  
K. LEFMANN ◽  
N. B. CHRISTENSEN ◽  
...  

There is strong evidence that magnetic interactions play a crucial role in the mechanism driving high-temperature superconductivity in cuprate superconductors. To investigate this we have done a series of neutron scattering measurements on La 2-x Sr x CuO 4 (LSCO) in an applied magnetic field. Below Tc the field penetrates the superconductor via an array of normal state metallic inclusions or vortices. Phase coherent superconductivity characterized by zero resistance sets in at the lower field-dependent irreversibility temperature (Tirr). We have measured optimally doped LSCO (x = 0.16, Tc = 38.5 K ) and under-doped LSCO ( x = 0.10, Tc = 29 K ); both have an enhanced antiferromagnetic response in a field. Measurements of the optimally doped system at H = 7.5 T show that sub-gap spin fluctuations first disappear with the loss of finite resistivity at Tirr, but then reappear at a lower temperature with increased lifetime and correlation length compared to the normal state. In the under-doped system elastic antiferromagnetism develops below Tc in zero field, and is significantly enchanced by application of a magnetic field. Phase coherent superconductivity is then established within the antiferromagnetic phase at Tirr; thus, the situation in under-doped LSCO is the reverse of that for the optimally doped LSCO where the zero-resistance state develops first before the onset of antiferromagnetism.


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