Unstable and elusive superconductors

TL;DR

This paper reviews experimental findings on metastable superconductors, highlighting electric field-induced conduction in CuCl and exploring potential mechanisms like sliding charge-density waves for high-temperature superconductivity, including surface effects in carbon materials.

Contribution

It presents new experimental results on electric field effects in CuCl and discusses possible collective charge transport mechanisms underlying high-temperature superconductivity.

Findings

Electric field induces conduction in CuCl resembling sliding CDWs.

Surface modifications in graphite and amorphous carbon can induce local superconductivity.

Potential link between charge-density waves and high-temperature superconductivity.

Abstract

We briefly review earlier and report original experimental results in the context of metastable or possible superconducting materials. We show that applied electric field induces conducting state in Copper Chloride (CuCl) whose characteristics resemble behavior of sliding charge-density-wave(s) (CDW). We discuss whether the sliding CDW or collective transport of similar ordered charge phase(s) may account for the problem of "high-temperature superconductivity" observed in this and other materials, including Cadmium Sulfide (CdS), metal-ammonia solutions, polymers, amorphous carbon and tungsten oxides. We also discuss a local superconductivity that occurs at the surface of graphite and amorphous carbon under deposition of foreign atoms/molecules.