title: Doping dependence of the pressure response of Tc in the SmO(1-x)F(x)FeAs superconductors.
abstract: The superconducting transition temperature of the high-Tc SmO1-xFxFeAs superconductors increases monotonically as the F-doping level x increases to 0.20. High-pressure magnetization experiments reveal a strong sensitivity of Tc to interatomic distances in the underdoped regime (x </= 0.12) with the pressure coefficient of Tc, d(ln Tc)/dP being strongly positive. However, as the doping level increases further to x = 0.15, we find that this sensitivity is strongly suppressed and at the same time, d(ln Tc)/dP sharply switches over to assume negative values with Tc decreasing with increasing applied pressure. The abrupt change in the pressure response of the superconducting properties of the SmO1-xFxFeAs phases coincides with the putative existence of a quantum critical point (QCP) near x approximately 0.14, as proposed by resistivity and Hall effect measurements.
authors.affiliation: Department of Chemistry, University of Durham, Durham DH1 3LE, UK.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takabayashi
authors.forename: Martin T
authors.initials: MT
authors.lastname: McDonald
authors.forename: Dionisis
authors.initials: D
authors.lastname: Papanikolaou
authors.forename: Serena
authors.initials: S
authors.lastname: Margadonna
authors.forename: G
authors.initials: G
authors.lastname: Wu
authors.forename: R H
authors.initials: RH
authors.lastname: Liu
authors.forename: X H
authors.initials: XH
authors.lastname: Chen
authors.forename: Kosmas
authors.initials: K
authors.lastname: Prassides