Superconducting proximity effect in flat band systems

TL;DR

This paper investigates the proximity-induced superconductivity in flat band dice lattice systems, revealing a critical chemical potential that influences the strength of the proximity effect and supercurrent behavior.

Contribution

It provides a theoretical analysis of superconducting proximity effects in flat band systems using self-consistent Bogoliubov-de Gennes calculations, identifying a critical chemical potential for the superconductor.

Findings

Proximity effect is enhanced above a critical chemical potential.

Supercurrent magnitude depends on the superconductor's chemical potential relative to the critical value.

Pairing amplitude increases significantly in the superconducting region when below the critical chemical potential.

Abstract

We study theoretically proximity-induced superconductivity and its inverse effect in dice lattice flat band model by considering Josephson junction with an s-wave pairing in the superconducting leads. Using self-consistent tight-binding Bogoliubov-de Gennes method, we show that there is a critical value for chemical potential of the superconductors depending on paring interaction strength over which for undoped normal region the proximity effect is enhanced. Whereas if the superconductor chemical potential is less than the critical one the proximity effect decreases regardless of normal region doping and in the meanwhile, the pairing amplitude of superconducting region increases significantly. Furthermore, we unveil that the supercurrent passing through the junction is large (vanishingly small) when the superconductor chemical potential is smaller (larger) than the critical value which increases as a function of normal region chemical potential.