Majorana Zero Modes in Semiconductor Nanowires in Contact with   Higher-$T_c$ Superconductors
  We analyze the prospects for stabilizing Majorana zero modes in semiconductor nanowires that are proximity-coupled to higher-temperature superconductors. We begin with the case of iron pnictides which, though they are s-wave superconductors, are believed to have superconducting gaps that change sign. We then consider the case of cuprate superconudctors. We show that a nanowire on a step-like surface, especially in an orthorhombic material such as YBCO, can support Majorana zero modes at an elevated temperature. 
Younghyun Kim, Jennifer Cano, Chetan Nayak
cond-mat.str-el cond-mat.supr-con