Search for new superconducting systems related to the infinite-layer family compounds: normal pressure sysnthesis and the role of doping

摘要

The usual scheme of two different block alyer intergrowth in order to describe high-T_c superconducting ceramics as modified to a three block layer scheme is reviewed.Based on this model,we remind the influence of bond mismatches,as the chemicla casuses for tress in the mterials,on structueal phase transition.Form such a point of view,we discuss the result of ion insertion into the layers at mabient pressue and their consequence on p- or n- type superconductivity,or the absence of any superconductin gphase.The role of the apical oxygen for charge-transfer through stress relief is pointed out as the likely chemical key ingredient for p-type superconductivity.