scholarly journals Publisher's Note: High-temperature superconductivity stabilized by electron-hole interband coupling in collapsed tetragonal phase ofKFe2As2under high pressure [Phys. Rev. B91, 060508(R) (2015)]

2015 ◽  
Vol 91 (9) ◽  
Author(s):  
Yasuyuki Nakajima ◽  
Renxiong Wang ◽  
Tristin Metz ◽  
Xiangfeng Wang ◽  
Limin Wang ◽  
...  
2016 ◽  
Vol 2 (1) ◽  
Author(s):  
Annette Bussmann-Holder ◽  
Jürgen Köhler ◽  
M.-H. Whangbo ◽  
Antonio Bianconi ◽  
Arndt Simon

AbstractThe recent report of superconductivity under high pressure at the record transition temperature of Tc =203 K in pressurized H2S has been identified as conventional in view of the observation of an isotope effect upon deuteration. Here it is demonstrated that conventional theories of superconductivity in the sense of BCS or Eliashberg formalisms cannot account for the pressure dependence of the isotope coefficient. The only way out of the dilemma is a multi-band approach of superconductivity where already small interband coupling suffices to achieve the high values of Tc together with the anomalous pressure dependent isotope coefficient. In addition, it is shown that anharmonicity of the hydrogen bonds vanishes under pressure whereas anharmonic phonon modes related to sulfur are still active.


2017 ◽  
Vol 19 (40) ◽  
pp. 27406-27412 ◽  
Author(s):  
Yanbin Ma ◽  
Defang Duan ◽  
Ziji Shao ◽  
Da Li ◽  
Liyuan Wang ◽  
...  

Invigorated by the high temperature superconductivity in some binary hydrogen-dominated compounds, we systematically explored high-pressure phase diagrams and superconductivity of a ternary Mg–Ge–H system usingab initiomethods.


2021 ◽  
Vol 23 (11) ◽  
pp. 6717-6724
Author(s):  
Mingyang Du ◽  
Zihan Zhang ◽  
Hao Song ◽  
Hongyu Yu ◽  
Tian Cui ◽  
...  

The contribution of optical and acoustic modes to the superconducting transition temperature. The calculated EPC parameter λ, critical temperature (Tc), critical temperature caused by the interaction of electrons with optical phonons (T0c) and acoustic phonons (Tacc).


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
T. L. Hung ◽  
C. H. Huang ◽  
L. Z. Deng ◽  
M. N. Ou ◽  
Y. Y. Chen ◽  
...  

AbstractThe rich phenomena in the FeSe and related compounds have attracted great interests as it provides fertile material to gain further insight into the mechanism of high temperature superconductivity. A natural follow-up work was to look into the possibility of superconductivity in MnSe. We demonstrated in this work that high pressure can effectively suppress the complex magnetic characters of MnSe, and induce superconductivity with Tc ~ 5 K at pressure ~12 GPa confirmed by both magnetic and resistive measurements. The highest Tc is ~ 9 K (magnetic result) at ~35 GPa. Our observations suggest the observed superconductivity may closely relate to the pressure-induced structural change. However, the interface between the metallic and insulating boundaries may also play an important role to the pressure induced superconductivity in MnSe.


Author(s):  
X. H. Zheng ◽  
J. X. Zheng

In superconductors, scattered electrons cover the entire surface of the Fermi sphere (circle in the figure, valency = 3). In the MP scheme in the article concerned, the shaded wedge confines coverage, causing errors in results.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
K. Mukasa ◽  
K. Matsuura ◽  
M. Qiu ◽  
M. Saito ◽  
Y. Sugimura ◽  
...  

AbstractThe interplay among magnetism, electronic nematicity, and superconductivity is the key issue in strongly correlated materials including iron-based, cuprate, and heavy-fermion superconductors. Magnetic fluctuations have been widely discussed as a pairing mechanism of unconventional superconductivity, but recent theory predicts that quantum fluctuations of nematic order may also promote high-temperature superconductivity. This has been studied in FeSe1−xSx superconductors exhibiting nonmagnetic nematic and pressure-induced antiferromagnetic orders, but its abrupt suppression of superconductivity at the nematic end point leaves the nematic-fluctuation driven superconductivity unconfirmed. Here we report on systematic studies of high-pressure phase diagrams up to 8 GPa in high-quality single crystals of FeSe1−xTex. When Te composition x(Te) becomes larger than 0.1, the high-pressure magnetic order disappears, whereas the pressure-induced superconducting dome near the nematic end point is continuously found up to x(Te) ≈ 0.5. In contrast to FeSe1−xSx, enhanced superconductivity in FeSe1−xTex does not correlate with magnetism but with the suppression of nematicity, highlighting the paramount role of nonmagnetic nematic fluctuations for high-temperature superconductivity in this system.


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