Singlet Reservoir Theory of Ambient Tc Granular Superconductivity in Monovalent Metal Nanostructures

TL;DR

This paper proposes a theory that Coulomb interactions in specific nanostructured regions of monovalent metals create singlet electron pair reservoirs, leading to ambient temperature granular superconductivity via the proximity Josephson effect.

Contribution

The paper introduces a novel singlet reservoir theory explaining ambient Tc superconductivity in monovalent metals, emphasizing the role of structural perturbations and Coulomb interactions.

Findings

Coulomb repulsions create nanoscale singlet electron pair reservoirs.

Structural perturbations enable superconductivity in monovalent metals.

All elemental monovalent metals may exhibit ambient Tc superconductivity under suitable conditions.

Abstract

Monovalent metals contain half filled band (HFB) of s-electrons. Emphasizing importance of Coulomb repulsions in HFB in 2D and 1D monovalent systems we sketched a theory (2018) for ambient temperature granular superconductivity reported by Thapa and Pandey (2018) in Au-Ag nanostructures (updated by Thapa et al., 2019). Sharpening our theory, we suggest that \textit{Coulomb repulsions in certain structurally perturbed regions (atomic clusters, stacking faults, grain boundaries etc.) create nanoscale reservoirs of singlet electron pairs}. These low dimensional patches are hybridized to a background 3D jellium metal and produce observed ambient Tc granular superconductivity via proximity Josephson effect. Using repulsive Hubbard model we show presence of singlet reservoirs and physics of doped Mott insulators. Needed charge transfer arises from differing electronegativities. Our theory predicts that \textit{all elemental monovalent (alkali, Cu, Ag and Au) metals, under suitable structural perturbations, are likely to exhibit ambient temperature superconductivity}.