First single crystal growth and structural analysis of superconducting layered bismuth oxyselenide; La(O,F)BiSe2

• Single crystals of La(O,F)BiSe2 were grown by a CsCl flux method.
• Crystal structure of La(O,F)BiSe2 was determined by single crystal X-ray analysis.
• La(O,F)BiSe2 shows superconductivity with a transition temperature of 3.6 K.
• Bonding nature and superconductivity of La(O,F)BiSe2 are discussed.

Single crystals of La(O,F)BiSe2 were successfully grown for the first time by a CsCl flux method. Single crystal X-ray structural analysis clearly showed that La(O,F)BiSe2 crystallizes with space group P4/nmm (lattice parameters a=4.1408(2) Å, c=14.1096(6) Å). The structure is composed of alternating BiSe2 and La(O,F) layers. The bond distances and angles are similar to those of La(O,F)BiS2. The bond valence sum calculation indicates the refined structure is slightly cation rich, suggesting the charge neutrality should be kept by modification of valence state of the cations. Magnetic susceptibility and resistivity measurements showed the compound is a superconductor with a transition temperature of 3.6 K, which is higher than that of as-grown La(O,F)BiS2.

Single crystal La(O,F)BiSe2 has been prepared by a CsCl flux method. The structural analysis implies that La(O,F)BiSe2 is a potential superconductor having a higher Tc under high pressure. Figure optionsDownload as PowerPoint slide