Phase Diagram and Quantum Critical Point in Newly Discovered Superconductors: SmO_{1-x}F_xFeAs

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dc.creatorLiu, R. H.
dc.creatorWu, G.
dc.creatorWu, T.
dc.creatorFang, D. F.
dc.creatorChen, H.
dc.creatorLi, S. Y.
dc.creatorLiu, K.
dc.creatorXie, Y. L.
dc.creatorWang, X. F.
dc.creatorYang, R. L.
dc.creatorDing, L.
dc.creatorHe, C.
dc.creatorFeng, D. L.
dc.creatorChen, X. H.
dc.date2008-04-14
dc.date2008-05-07
dc.date.accessioned2026-07-07T09:59:51Z
dc.date.available2026-07-07T09:59:51Z
dc.descriptionThe magnetic fluctuations associated with a quantum critical point (QCP) are widely believed to cause the non-Fermi liquid behaviors and unconventional superconductivities, for example, in heavy fermion systems and high temperature cuprate superconductors. Recently, superconductivity has been discovered in iron-based layered compound $LaO_{1-x}F_xFeAs$ with $T_c$=26 K\cite{yoichi}, and it competes with spin-density-wave (SDW) order\cite{dong}. Neutron diffraction shows a long-rang SDW-type antiferromagnetic (AF) order at $\sim 134$ K in LaOFeAs\cite{cruz,mcguire}. Therefore, a possible QCP and its role in this system are of great interests. Here we report the detailed phase diagram and anomalous transport properties of the new high-Tc superconductors $SmO_{1-x}F_xFeAs$ discovered by us\cite{chenxh}. It is found that superconductivity emerges at $x\sim$0.07, and optimal doping takes place in the $x\sim$0.20 sample with highest $T_c \sim $54 K. While $T_c$ increases monotonically with doping, the SDW order is rapidly suppressed, suggesting a QCP around $x \sim$0.14. As manifestations, a linear temperature dependence of the resistivity shows up at high temperatures in the $x<0.14$ regime, but at low temperatures just above $T_c$ in the $x>0.14$ regime; a drop in carrier density evidenced by a pronounced rise in Hall coefficient are observed, which mimic the high-$T_c$ cuprates. The simultaneous occurrence of order, carrier density change and criticality makes a compelling case for a quantum critical point in this system.
dc.description10 pages, 4 figures
dc.identifierhttps://arxiv.org/abs/0804.2105
dc.identifierhttp://arxiv.org/abs/0804.2105
dc.identifierPhys. Rev. Lett 101, 087001(2008)
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/168173
dc.subjectSuperconductivity
dc.subjectMaterials Science
dc.subjectStrongly Correlated Electrons
dc.titlePhase Diagram and Quantum Critical Point in Newly Discovered Superconductors: SmO_{1-x}F_xFeAs
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