Collapse of the Fe-vacancy order and successive phase transitions in superconducting KxFe2-ySe2 (0.7 \leg x \leg 0.8, 0.2 \leg y \leg 0.3)

J. Q. Li, Y. J. Song, H. X. Yang +6

The Fe-based superconducting KxFe2-ySe2 (0.6 {\leg} x {\leg} 1, 0.2{\leg} y {\leg} 0.4) compounds, unlike the well-known RFe2As2 (R = Ba, Sr, Ca) superconductors, contain complex s…