Zhi-An Ren

Superconductivity in Boron-doped SiC

We report superconductivity in heavily boron-doped bulk silicon carbide related to the diamond structure. The compound exhibits zero resistivity and diamagnetic susceptibility below a critical temperature T c of ∼1.4 K, and an effective boron doping concentration higher than 10 21 cm -3 . We present the H – T phase diagram of this new superconducting compound determined from AC susceptibility. In finite DC magnetic fields a clear hysteresis was observed between cooling and subsequent warming runs. This indicates, in contrast with the type-II superconductivity in boron-doped diamond and silicon, that a type-I superconductivity with a critical field H c (0) of about 100 Oe is realized in boron-doped SiC. Moreover, the specific-heat shows a clear jump at T c , demonstrating bulk nature of the superconductivity.

Superconductivity in heavily boron-doped silicon carbide

Abstract The discoveries of superconductivity in heavily boron-doped diamond in 2004 and silicon in 2006 have renewed the interest in the superconducting state of semiconductors. Charge-carrier doping of wide-gap semiconductors leads to a metallic phase from which upon further doping superconductivity can emerge. Recently, we discovered superconductivity in a closely related system: heavily boron-doped silicon carbide. The sample used for that study consisted of cubic and hexagonal SiC phase fractions and hence this led to the question which of them participated in the superconductivity. Here we studied a hexagonal SiC sample, free from cubic SiC phase by means of x-ray diffraction, resistivity, and ac susceptibility.