Superconductivity and its Enhancement under High Pressure in "F-free" Single Crystals of CeOBiS${}_2$

Abstract

"F-free" CeOBiS${}_2$ single crystals have successfully grown, thoroughly eliminating a concern about F-contamination by using a high-purity CsCl flux. The obtained crystals have a plate-like shape with a size of 1.0-3.0 mm in the well-developed plane. Single crystal X-ray structural analysis clearly revealed that the CeOBiS${}_2$ crystallizes with a space group $P4/nmm$ (with lattice parameters of $a$ = 4.0189(6) Å, $c$ = 13.573(2) Å). The bond valence sum estimation and X-ray photoelectron spectroscopy analysis showed that the chemical state of Ce was in the mixed valence of Ce${}^{3+}$ and Ce${}^{4+}$. The single crystals show superconductivity with zero resistivity at $\sim$1.3 K. This is the first conclusive evidence of superconductivity driven by Ce valence fluctuation in surely non-doped CeOBiS${}_2$. The superconducting transition temperature was enhanced up to $\sim$3.8 K by applying hydrostatic pressure.

27 pages, 8 figures, J. Alloys and Compd. (2017)

References in corpus (14)

• Superconductivity at 43 K in Samarium-arsenide Oxides $SmFeAs{O}_{1-x}{F}_x$
• Superconductivity Appears in the Vicinity of an Insulating-Like Behavior in CeO${}_{1-x}$F${}_x$BiS${}_2$
• Superconductivity of F-substituted LnOBiS2 (Ln = La, Ce, Pr, Nd, Yb) compounds
• Pressure Study of BiS2-Based Superconductors Bi4O4S3 and La(O,F)BiS2
• Checkerboard stripe electronic state on cleaved surface of NdO${}_{0.7}$F${}_{0.3}$BiS${}_2$ probed by scanning tunneling microscope
• Site Selectivity on Chalcogen Atoms in Superconducting La(O,F)BiSSe
• First single crystal growth and structural analysis of superconducting layered bismuth oxyselenide; La(O,F)BiSe2
• Superconductivity in CeOBiS2 with cerium valence fluctuation
• Coexistence of ferromagnetism and superconductivity in CeO${}_{0.3}$F${}_{0.7}$BiS${}_2$
• Growth and superconducting anisotropies of F-substituted LaOBiSe2 single crystals
• High-Tc Phase of PrO0.5F0.5BiS2 single crystal induced by uniaxial pressure
• Optical spectroscopy study of Nd(O,F)BiS2 single crystals
• Pressure-induced phase transition for single crystalline LaO0.5F0.5BiSe2
• Enhanced superconductivity in F-doped LaO1-xFxBiSSe

Cited by in corpus (7)

• High pressure effects on non-fluorinated BiS2-based superconductors La${}_{1-x}$M${}_x$OBiS${}_2$ (M = Ti and Th)
• Growth of superconducting Sm(O,F)BiS2 single crystals
• Growth and characterization of (La,Ce)OBiS2 single crystals
• Growth and transport properties under high pressure of PrOBiS2 single crystals
• Effects of equivalent composition on superconducting properties of high-entropy REOBiS${}_2$ (RE = La, Ce, Pr, Nd, Sm, Gd) single crystals
• Investigation of superconductivity in Ce-doped (La,Pr)OBiS2 single crystals
• Superconducting phase diagram of Sb and Se substitution in CeOBiS2 single crystals