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arXiv · 0805.0355

Interpretation of high-pressure experiments on FeAs superconductors

Xiuqing Huang
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Abstract

In two recent articles (cond-mat/0606177 and arXiv:0804.1615), we have suggested a unified theory of superconductivity based on the real-space spin-parallel electron pairing and superconducting mechanism and have shown that the stable hexagonal and tetragonal vortex lattices (the optimal doping phases) can be expected in the newly discovered LaO{1-x}F{x}FeAs (x0=1/7=0.1428) and SmO{1-x}F{x}FeAs (x0=1/6=0.1667), respectively. In this paper, we present a theoretical study of the effects of hydrostatic and anisotropic pressure on the superconducting transition temperature Tc of the Fe-based layered superconductors based on the above mentioned theory. Our results indicate a strong doping-dependent pressure effects on the Tc of this compound system. Under high hydrostatic pressure, we find that dTc/dP is negative when x>x0 (the so-called overdoped region) and is positive when x 1/6) (arXiv:0804.1582). Furthermore, Tc of both overdoped and underdoped samples shows an increase with uniaxial pressure in the charge stripe direction and a decrease with pressure in the direction perpendicular to the stripes. We suggest that the mechanism responsible for the pressure effect is not specific to the iron-based family and it may also be applicable to other superconducting materials.

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Xiuqing Huang. 2008-05-03. Interpretation of high-pressure experiments on FeAs superconductors. https://arxiv.org/abs/0805.0355

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