Theory of Confined High Tc Superconductivity in Monovalent Metals

Abstract

Monovalent non-transition metals are robust Fermi liquids. They defy superconductivity even at lowest temperatures (Li is a minor exception:Tc ≈ 0.4 mK). However, Thapa and Pandey [8] have recently reported signals for ambient temperature granular superconductivity in Ag nanoparticle embedded in Au matrix. We develop a theory, where competing superconducing, CDW and SDW orders lose and get confined (go off-shell). They leave behind a robust Fermi liquid on-shell. A single half filled band crossing the Fermi level provides a number of special k-space regions for singlet stabilizing umklapp pair scattering and superconductivity stabilizing repulsive pair scattering. Carefully designed perturbations could deconfine a confined superconductivity. We suggest that electron transfer (doping) from Ag nanoparticles to Au matrix (with a higher electronegativity), quasi 2d structural reconstructions (e.g., 9R structure) at Ag-Au interfaces etc., bring out confined superconductivity. Beneath a calm Fermi sea, strong supercurrents may exist in several metals.

A holographic superconductor forced through interactions

“…It would also be worth investigating, whether such a mechanism can be used to increase T c , even within the paradigm of BCS theory. Such a novel mechanism would be very interesting, particularly in the backdrop of recent deliberations on [22], where there has been some fascinating claims on achieving superconductivity at room temperature (also see [23,24], for relevant discussions on the reported experimental observation).…”

Unconventional properties of engineered Au–Ag nanostructures

“…Theoretical efforts to explain the unconventional response of these materials have increasingly emerged. Significant theoretical views include proposals regarding the role of strong correlations, exchange, as well as the advent of insulating character in these systems [19,[91][92][93].…”