2008/05/03 by Xiuqing Huang, Huang, Xiuqing
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Iron-based superconductors research #Physics of Superconductivity and Magnetism #Rare-earth and actinide compounds #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con) #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.0805.0355
9 pages, 10 figures
arxiv created 2008/05/03 · openalex publication_date 2008/05/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 LaO1-xFxFeAs (x0=1/7=0.1428) and SmO1-xFxFeAs (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<x0 (the so-called underdoped region). Qualitatively, our finding is in good agreement with the existing experimental data in LaO1-xFxFeAs (x=0.11<1/7) (arXiv:0803.4266) and SmO1-xFxFeAs (x=0.13<1/6 and x=0.3>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.