Proximity Effect of Magnesium Diboride on Single-Walled Carbon Nanotube: an Ab Initio Study

Abstract

Magnesium diboride (MgB2) superconductor with excellent physical properties continues to attract the attention of researchers since its discovery. It derives its versatility from the absence of weak links, large coherence length, and small anisotropy. On the other hand, reports of superconductivity in small-diameter single-walled carbon nanotubes (SWCNTs) suspended between superconducting contacts and proximity induced supercurrents in Ta/SWNTs/Au junctions have also aroused great interest in the scientific community. Proximity induced superconductivity in SWCNTs has opened up new frontiers of research which will lead to many novel discoveries. This paper reports ab initio investigations on the proximity effect of MgB2 on the electronic structure of a SWCNT. Condensation of electronic states is observed in the electronic band structure of the pristine SWCNT when MgB2 is held in proximity. An additional band gap is generated below the lowest energy state of the valence band of the pristine CNT which we suggest, is due to Cooper pair formation. This leads to the prediction that SWCNTs will show superconducting properties in proximity of MgB2. We envision MgB2-coated SWCNTs as a novel nanomaterial that has a combination of proximity induced superconductivity and inherently unique mechanical and optical properties of SWCNTs.