Triplet Superconductivity from Nonlocal Coulomb Repulsion in an Atomic Sn Layer Deposited onto a Si(111) Substrate

TL;DR

This paper investigates how nonlocal Coulomb interactions in a doped tin monolayer on silicon can lead to unconventional triplet superconductivity, revealing the importance of extended Hubbard interactions.

Contribution

It demonstrates that extended Coulomb interactions are essential for triplet pairing in a doped Sn/Si(111) system, using renormalization group analysis.

Findings

Triplet pairing is driven by nonlocal Coulomb repulsion.

f-wave pairing at moderate doping, p-wave at higher doping.

Extended Hubbard interactions are crucial for unconventional superconductivity.

Abstract

Atomic layers deposited on semiconductor substrates introduce a platform for the realization of the extended electronic Hubbard model, where the consideration of electronic repulsion beyond the onsite term is paramount. Recently, the onset of superconductivity at 4.7K has been reported in the hole-doped triangular lattice of tin atoms on a silicon substrate. Through renormalization group methods designed for weak and intermediate coupling, we investigate the nature of the superconducting instability in hole-doped Sn/Si(111). We find that the extended Hubbard nature of interactions is crucial to yield triplet pairing, which is f-wave (p-wave) for moderate (higher) hole doping. In light of persisting challenges to tailor triplet pairing in an electronic material, our finding promises to pave unprecedented ways for engineering unconventional triplet superconductivity.