Strengthening of the superconductivity by real space decimation of the flat band states

TL;DR

This paper demonstrates that selectively removing flat band states in a lattice can enhance superconductivity, challenging traditional uniform pairing assumptions and offering new experimental avenues in nanostructures.

Contribution

It reveals that decimating flat band eigenstates can boost superfluid weight, providing a novel method to control superconductivity beyond standard models.

Findings

Decimation of flat band states enhances superfluid weight.

Uniform pairing hypothesis can underestimate superconductivity.

Potential experimental realization in nanostructured materials.

Abstract

In contrast to standard BCS superconductivity, that in flat bands (FBs) possesses an interesting degree of freedom that enables the control of the superfluid weight (SFW), referred to as the quantum metric (QM). In the present work, we consider the stub lattice and study the impact of the dilution of FB eigenstates on superconductivity. Among the most remarkable results, it is revealed that the SFW can be boosted by the decimation of the FB eigenstates. In addition, it is shown that the widely used uniform pairing hypothesis systematically predicts the suppression of the SFW, appears misleading and qualitatively incorrect. With the great progress in nanotechnologies, we believe that our findings could be realised and tested experimentally in covalent organic frameworks or in decorated structures in which defects/vacancies/ad-atoms are created/deposited in a controlled manner and even in multilayered structures with intercalated atoms.