Superconductivity in Boron-doped SiC

Abstract

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 À3 . 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 ð0Þ 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.

Characterization of neutral boron-silicon clusters using infrared spectroscopy: The case of Si6B

“…Interestingly, similar effects have also been predicted for small B-doped silicon clusters [19]. Efforts have been made to increase Tc in B-doped silicon [16,20,21].…”

“…With the discovery of a superconducting transition at about 40 K in MgB2 [10], there has been great interest in boron-doped materials as promising superconductors, including boron-doped diamond [11,12], silicon [13], and silicon carbide [14][15][16]. In crystalline phases, doping of group IV elements with boron as the source of holedoping has been shown to induce superconductivity [12,13,17].…”

Electronic structures and mechanical properties of boron and boron-rich crystals (Part I)

“…Since then, the superconductivity has been discovered in heavily doped diamond, which was first synthesized at high pressure [6]. This opens a new stream of superconducting research in heavily doped semiconductors [7][8][9].…”

Electric-field-driven hole carriers and superconductivity in diamond

“…This new class of superconductors with directional covalent bonding, most likely electron-phonon mediated, consists not only of doped diamond, but also other doped semiconductors 3 . In the 1960's, it was predicted that doping a semiconductor with many-valley features in the band structure would induce an effective interaction to overcome the Coulomb repulsion 4,5 ; this mechanism was confirmed in subsequent experiments on reduced SrTiO 3 6 and Ge 1−x Te 7 , albeit with rather low transition temperatures, T c , of at most 0.5 K. Nevertheless, the 2004 discovery [8][9][10] of superconductivity in boron-doped diamond has excited interest in this new class of superconductors, which now also extends to silicon 11 and SiC 12,13 . In doped diamond, the concentration of B dopants exceeded a critical value responsible for a metal-insulator transition, which eventually induced superconductivity around 7-9 K with carrier densities of ∼10 21 cm −38,14 .…”