Disorder-driven electronic localization and phase separation in superconducting Fe1+yTe0.5Se0.5 single crystals
arXiv:1209.1211 · doi:10.1103/PhysRevB.82.144523
Abstract
We have investigated the influence of Fe-excess on the electrical transport and magnetism of Fe1+yTe0.5Se0.5 (y=0.04 and 0.09) single crystals. Both compositions exhibit resistively determined superconducting transitions (Tc) with an onset temperature of about 15 K. From the width of the superconducting transition and the magnitude of the lower critical field Hc1, it is inferred that excess of Fe suppresses superconductivity. The linear and non-linear responses of the ac-susceptibility show that the superconducting state for these compositions is inhomogeneous. A possible origin of this phase separation is a magnetic coupling between Fe-excess occupying interstitial sites in the chalcogen planes and those in the Fe-square lattice. The temperature derivative of the resistivity drho/dT in the temperature range Tc < T < Ta with Ta being the temperature of a magnetic anomaly, changes from positive to negative with increasing Fe. A log 1/T divergence of the resistivity above Tc in the sample with higher amount of Fe suggests a disorder driven electronic localization.
7 pages
References in corpus (16)
- Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
- Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeOFFeAs
- Superconductivity at 36 K in beta-Fe1.01Se with the compression of the interlayer separation under pressure
- Density functional study of FeS, FeSe and FeTe: Electronic structure, magnetism, phonons and superconductivity
- Superconductivity at 27 K in tetragonal FeSe under high pressure
- Superconductivity and Phase Diagram in the Iron-based Arsenic-oxides ReFeAsO1-delta (Re = rare earth metal) without F-Doping
- Extreme Sensitivity of Superconductivity to Stoichiometry in FeSe (Fe1+dSe)
- Superconductivity close to magnetic instability in Fe(Se1-xTex)0.82
- Tellurium substitution effect on superconductivity of the alpha-phase Iron Selenide
- Incommensurate magnetic order in the alpha-Fe(Te,Se) superconductor systems
- First-order magnetic and structural phase transitions in FeSeTe
- Bulk Superconductivity at 14 K in Single Crystals of Fe1+yTexSe1-x
- Bi-collinear antiferromagnetic order in the tetragonal -FeTe
- Fermi surface topology and low-lying quasiparticle dynamics of parent FeTe/Se Superconductor by orbital-polarization resolved ARPES
- Density Functional Study of Excess Fe in FeTe: Magnetism and Doping
- Short-range incommensurate magnetic order near the superconducting phase boundary in Fe(1+d)Te(1-x)Se(x)