Origin of the Higher-$T_\rm{c}$ Phase in the K${}_x$Fe${}_{2-y}$Se${}_2$ System

Masashi Tanaka, Yusuke Yanagisawa, Masaya Fujioka +7

Single crystals of K${}_x$Fe${}_{2-y}$Se${}_2$ are prepared by quenching at various temperatures. The crystals obtained at higher quenching temperatures have a surface morphology with me…