Transport properties and electronic phase diagram of single-crystallineCa10(Pt3As8)

Abstract

Sizable single-crystalline samples of Ca 10 (Pt 3 As 8 )((Fe 1−x Pt x ) 2 As 2 ) 5 (the 10-3-8 phase) with 0 x < 0.1 have been grown and have been systematically characterized via x-ray diffraction, magnetic, and transport measurements. The unsubstituted sample is a heavily doped semiconductor with no sign of magnetic order down to 2 K. With increasing Pt content, the metallic behavior appears, and superconductivity is realized for x 0.023. T c rises to its maximum of approximately 13.6 K at the doping level of x ∼ 0.06 and then decreases for higher x values. The electronic phase diagram of the 10-3-8 phase was mapped out based on the magnetic and transport measurements. The mass anisotropy parameter ∼ 10, obtained from resistive measurements in magnetic fields, indicates a relatively large anisotropy in the iron-based superconductor family. This strong two-dimensional character may lead to the absence of magnetic order. A linear T dependence of susceptibility at high temperatures is observed, indicating that spin fluctuations exist in the underdoped region as in most of the Fe-pnictide superconductors.

Unravelling the mechanism of the semiconducting-like behavior and its relation to superconductivity in (CaFe1−xPtxAs)10Pt3<

“…Interestingly, the coherent component begins to lose strength well above the structural and magnetic transitions [Figs.3(d) and 4(a)]. The parent material is highly 2D [29], the interlayer magnetic coupling is very weak, and is easily destroyed by doping [20]. Before three dimensional (3D) long-range AFM order can be established, intralayer 2D short-range AFM fluctuations are present [30,31].…”

Superconducting properties and pseudogap from preformed Cooper pairs in the triclinic(CaFe1−xPtxAs)10Pt3

“…Their structural and physical properties still remain a subject of current investigation [4][5][6][7]. An interesting peculiarity of these systems is that they display a large difference in their optimal critical temperature T c and ground-state properties depending on the amount of Pt in the intermediary Pt n As 8 spacer layer (n = 3 or 4) [1,4,8].…”

Temperature dependence of the superconducting energy gaps in Ca9.35La0.65(Pt3As8)(Fe2As2)5 single crystal

“…On the other hand, the parent compound Ca 10 (Pt 3 As 8 )(Fe 2 As 2 ) 5 shows a triclinic crystal structure that becomes semiconducting and antiferromagnetically ordered below T N  ~ 120 K without any reduction in the crystal symmetry 10 . Electron doping using La and Pt substitution for the Ca and Fe sites can induce superconductivity and a semiconductor-metal transition, as well as the suppression of antiferromagnetic ordering, with a maximum T c for each substitution of ~32 K and ~15 K, respectively 11–13 .…”