Investigation of superconductivity in isoelectronic and related compounds of MgB2

Abstract

MgB2 related compounds such as the borocarbides LiBC and MgB2C2, and the nominal compound of "BeB2'' were synthesized and existence of superconductivity investigated by low field magnetic susceptibility measurements. Superconductivity was observed not to occur in all of the compounds down to a temperature of 2 K which agrees with recent calculations on the borocarbides. Hole doping of MgB2C2 has been predicted to be favorable for superconductivity due to the fiat band (in the T-Y direction) similar to one in MgB2-Attempts to substitutionally hole dope MgB2C2 with alkali metals were carried out for the first time, with Li doping demonstrated to appear to be feasible, but in the present samples superconductivity was not observed. © 2002 The Physical Society of Japan.