Possible Mechanism for Superconductivity in Sulfur - Common Theme for Unconventional Superconductors?

TL;DR

This paper proposes a possible mechanism for sulfur's high-pressure superconductivity involving emergent 2D conducting planes, drawing parallels with unconventional superconductors like cuprates and 2D electron systems.

Contribution

It introduces a novel hypothesis that sulfur's superconductivity arises from 2D conducting planes formed by planar rings, linking it to mechanisms in other unconventional superconductors.

Findings

Superconductivity in sulfur appears at specific high-pressure phases.

The proposed mechanism involves emergent 2D conducting planes in sulfur.

Connections are drawn between sulfur's behavior and other unconventional superconductors.

Abstract

Sulfur has recently been found to be a superconductor at high pressure. At ~93 GPa Tc is 10.1 K, and the sulfur is in a base-centered orthorhombic (b.c.o) structure. At ~160 GPa Tc is 17 K and sulfur is in a rhobohedral (b-Po) structure. The mechanism for superconductivity in sulfur is not known; in particular, a band-structure calculation does not find superconductivity in sulfur until 500 GPa. Following work by Anderson, in a 2D strongly interacting non-fermi liquid system with some degree of disorder at T=0, the only known conducting state is a superconductor. Following this idea it has been suggested that both the HTc cuprates and the 2D electron gas systems are superconductors with planar conducting planes. Similarly, here we suggest that the mechanism for conductivity in sulfur are 2D conducting planes which emerge as the planare rings in sulfur at lower pressure pucker at higher pressures (b.c.o. and b-Po). As well, we note some other consequences for study of HTc materials of Anderson's work.