Superconductivity in Ba1-xKxTi2Sb2O (0 < x < 1) controlled by charge doping

Abstract

The solid solution of antimonide-oxides Ba1-xKxTi2Sb2O (0 < x < 1) has been synthesized by solid-state reactions and characterized by X-ray powder diffraction (CeCr2Si2C-type structure; P4/mmm, Z = 1). The crystal structure consists of Ti2Sb2O-layers that are stacked with layers of barium atoms along the c-axis. BaTi2Sb2O is a known superconductor with a critical temperature (Tc) of 1.2 K. Substitution of barium through potassium raises Tc up to 6.1 K at 12 % potassium, while no superconductivity emerges with concentrations higher than 20 %. Anomalies in electrical transport and magnetic susceptibility indicate charge density wave (CDW) instabilities. The CDW transition temperatures (Ta) decrease from 50 K in the parent compound to 28 K at 10 % potassium substitution. No CDW transition was detected at higher concentrations, and no evidence for a reduction of the lattice symmetry below Ta was found. The lattice parameters vary linearly while the unit cell volume increases with higher potassium concentrations. The phase diagrams Tc(x) and Ta(x) of Ba1-xKxTi2Sb2O are remarkably similar to the known series Ba1-xNaxTi2Sb2O (0 < x < 0.33) in spite of the reverse volume effect. From this we conclude that the charge and not the volume determines the phase diagrams of these superconducting antimony oxides.

12 pages, 5 figures

References in corpus (10)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Direct observation of competition between superconductivity and charge density wave order in YBa2Cu3Oy
• Superconductivity and Crystal Structures of (Ba1-xKx)Fe2As2 (x = 0 - 1)
• Ba1-xNaxTi2Sb2O (0.0 <= x <= 0.33): A Layered Titanium-based Pnictide Oxide Superconductor
• Pressure dependence of the charge density wave in 1T-TaS2 and its relation to superconductivity
• Electronic structure, disconnected Fermi surfaces and antiferromagnetism in the layered pnictide superconductor Na${}_x$Ba${}_{1-x}$Ti${}_2$Sb${}_2$O
• S wave superconductivity in newly discovered superconductor BaTi${}_2$Sb${}_2$O revealed by ${}^{121/123}$Sb-NMR/Nuclear Quadrupole Resonance measurements
• Electron-phonon superconductivity and charge density wave instability in the layered titanium-based pnictide BaTi${}_2$Sb${}_2$O
• Conventional superconductivity and charge-density-wave ordering in Ba1-xNaxTi2Sb2O
• Weak Coupling BCS-like Superconductivity in the Pnictide Oxide Ba${}_{1-x}$Na${}_x$Ti${}_2$Sb${}_2$O (x=0 and 0.15)

Cited by in corpus (14)

• Exploration of new superconductors and functional materials and fabrication of superconducting tapes and wires of iron pnictides
• Weak metal-metal transition in the vanadium oxytelluride Rb${}_{1-\delta }$V${}_2$Te${}_2$O
• Superconductivity in rubidium substituted Ba1-xRbxTi2Sb2O
• Phonon dispersions and Fermi surfaces nesting explaining the variety of charge ordering in titanium-oxypnictides superconductors
• Double stage nematic bond-ordering above double stripe magnetism: application to BaTi${}_2$Sb${}_2$O
• Superconductivity in titanium-based pnictide oxide compounds
• Coexistence of superconductivity and density wave in $\mathrm{B}{\mathrm{a}}_2\mathrm{T}{\mathrm{i}}_2\mathrm{F}{\mathrm{e}}_2\mathrm{A}{\mathrm{s}}_4\mathrm{O}$: an optical spectroscopy study
• Commensurate lattice distortion in the layered titanium oxypnictides Na${}_2$Ti${}_{2}P{n}_2$O ($Pn=$ As, Sb) determined by X-ray diffraction
• New phase transition in Na${}_2$Ti${}_2$As${}_2$O revealed by Raman scattering
• Exotic phase transition and superconductivity in layered titanium-oxypnictides implied by a computational phonon analysis
• Revealing the hidden order in BaTi2As2O via nuclear magnetic resonance
• Chemistry and physics of layered oxychalcogenides containing an anti-cuprate type square lattice
• Theory for doping trends in titanium oxypnictide superconductors
• Two superconducting phases and their characteristics in layered BaTi2(Sb1-xBix)2O with x=0.16