# Superconductivity in an organometallic compound

## TL;DR

This paper reports the discovery of superconductivity at 3.6 K in a potassium-doped organometallic compound, demonstrating its potential for new organic superconductors and expanding the understanding of quantum phenomena in such materials.

## Contribution

It provides the first experimental evidence of superconductivity in an organometallic compound, specifically tri-o-tolylbismuthine, and identifies the benzene ring as the essential superconducting unit.

## Key findings

- Superconductivity observed at 3.6 K in potassium-doped tri-o-tolylbismuthine.
- Evidence of Meissner effect and zero-resistivity confirming superconductivity.
- The compound is classified as a type-II superconductor.

## Abstract

Organometallic compounds constitute a very large group of substances that contain at least one metal-to-carbon bond in which the carbon is part of an organic group. They have played a major role in the development of the science of chemistry. These compounds are used to a large extent as catalysts (substances that increase the rate of reactions without themselves being consumed) and as intermediates in the laboratory and in industry. Recently, novel quantum phenormena such as topological insulators and superconductors were also suggested in these materials. However, there has been no report on the experimental exploration for the topological state. Evidence for superconductivity from the zero-resistivity state in any organometallic compound has not been achieved yet, though much efforts have been devoted. Here we report the experimental realization of superconductivity with the critical temperature of 3.6 K in a potassium-doped organometallic compound, $ i.e.$ tri-$o$-tolylbismuthine with the evidence of both the Meissner effect and the zero-resistivity state through the $dc$ and $ac$ magnetic susceptibility and resistivity measurements. The obtained superconducting parameters classify this compound as a type-II superconductor. The benzene ring is identified to be the essential superconducting unit in such a phenyl organometallic compound. The superconducting phase and its composition are determined by the combined studies of the X-ray diffraction and theoretical calculations as well as the Raman spectroscopy measurements. These findings enrich the applications of organometallic compounds in superconductivity and add a new electron-acceptor family for organic superconductors. This work also points to a large pool for finding superconductors from organometallic compounds.