Possible Existence of Superconductivity in the Quasi-One-Dimensional Conductor Li$_{0.9}$Mo${_6}$O$_{17}$ at Ultrahigh Magnetic Fields, $H \geq 45 \ T$

TL;DR

This paper proposes a theoretical model showing that superconductivity can persist in quasi-one-dimensional conductors under ultrahigh magnetic fields, suggesting the existence of a triplet superconducting phase in Li$_{0.9}$Mo$_6$O$_{17}$.

Contribution

It derives a gap equation indicating conditions under which superconductivity survives high magnetic fields in Q1D conductors, proposing a possible triplet phase in Li$_{0.9}$Mo$_6$O$_{17}$.

Findings

Superconductivity can withstand high magnetic fields if the coherence length is less than the inter-plane distance.

A triplet superconducting phase may exist in Li$_{0.9}$Mo$_6$O$_{17}$ at ultrahigh magnetic fields.

Superconductivity could be stable at arbitrarily high magnetic fields under certain conditions.

Abstract

We derive a so-called gap equation for superconductivity in a quasi-one-dimensional (Q1D) layered conductor in a magnetic field, which is parallel to both its conducting plane and its conducting axis. This equation demonstrates that the orbital destructive effects against superconductivity cannot destroy it, if the perpendicular to the plane coherence length is less than the inter-plane distance. On the basis of our results, we suggest arguments that some triplet superconducting phase was indeed discovered in ultrahigh magnetic fields in the Q1D superconductor Li$_{0.9}$Mo$_6$O$_{17}$ [see Xiaofeng Xu et al., Phys. Rev. Lett., $\bf{102}$, 206602 (2009).] We also discuss a possibility that the above-mentioned superconducting phase can be stable at arbitrary high magnetic fields.