Evolution of superconductivity in isovalent Te-substituted KxFe2-ySe2 crystals

Abstract

We report the evolution of superconductivity and the phase diagram of the KxFe2-ySe2-zTez (z=0-0.6) crystals grown by a simple one-step synthesis. No structural transition is observed in any crystals, while lattice parameters exhibit a systematic expansion with Te content. The Tc exhibits a gradual decrease with increasing Te content from Tconset = 32.9 K at z = 0 to Tconset = 27.9 K at z = 0.5, followed by a sudden suppression of superconductivity at z = 0.6. Upon approaching a Te concentration of 0.6, the shielding volume fraction decreases and eventually drops to zero. Simultaneously, hump positions in r-T curve shift to lower temperatures. These results suggest that isovalent substitution of Te for Se in KxFe2-ySe2 crystals suppresses the superconductivity in this system.

10 pages, 1 table, 8 figures

References in corpus (16)

• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• Superconductivity at 27 K in tetragonal FeSe under high pressure
• Competing Orders and Spin-Density-Wave Instability in La(O${}_{1-x}$F${}_x$)FeAs
• Tellurium substitution effect on superconductivity of the alpha-phase Iron Selenide
• Heavily electron-doped electronic structure and isotropic superconducting gap in AxFe2Se2 (A=K,Cs)
• Substitution Effects on FeSe Superconductor
• Superconductivity at 32 K in single crystal Rb${}_{0.78}$Fe${}_2$Se${}_{1.78}$}
• Transport properties of the new Fe-based superconductor KxFe2Se2 (Tc = 33 K)
• Intrinsic phase separation in superconducting K0.8Fe1.6Se2 (Tc= 31.8 K) single crystals
• KFe_2Se_2 is the parent compound of K-doped iron selenide superconductors
• Iron vacancy superstructure and possible room temperature antiferromagnetic order in superconducting Cs_{y}Fe_{2-x}Se_2
• Mott transition in Modulated Lattices and Parent Insulator of (K,Tl)yFexSe2 Superconductors
• Electronic and magnetic structures of ternary iron selenides AFe${}_2$Se${}_2$ (A=K, Cs, or Tl)
• Spin reorientation in TlFe1.6Se2 with complete vacancy ordering
• Metastable superconducting state in quenched KxFe2-ySe2
• One-step synthesis of KxFe2-ySe2 single crystals for high critical current density

Cited by in corpus (5)

• Spin fluctuations in iron pnictides and chalcogenides: From antiferromagnetism to superconductivity
• Origin of Pressure-induced Superconducting Phase in K${}_x$Fe${}_{2-y}$Se${}_2$ studied by Synchrotron X-ray Diffraction and Spectroscopy
• Chemical enhancement of superconductivity in LaRu3Si2 with mode-selective coupling between kagome phonons and flat bands
• Connection between ambient-pressure and pressure-induced superconducting phases in alkaline iron selenide superconductors
• Annealing Effect on Microstructure and Superconductivity of KxFeySe2 Synthesized by an Easy One-step Method