Doping fingerprints of spin and lattice fluctuations in moir\'e superlattice systems

TL;DR

This paper investigates spin-fluctuation-mediated superconductivity in twisted transition metal dichalcogenide bilayers, revealing doping-dependent transition temperatures and identifying experimental signatures to distinguish pairing mechanisms.

Contribution

It provides a quantitative analysis of spin-fluctuation pairing in moiré systems, predicting a superconducting dome and doping fingerprints to differentiate from phonon-mediated superconductivity.

Findings

Superconducting transition temperature forms a dome with doping.

Doping dependence of Tc reveals fingerprints of pairing mechanism.

Comparison with phonon-mediated pairing highlights distinct signatures.

Abstract

Twisted Van der Waals systems offer the unprecedented possibility to tune different states of correlated quantum matter with an external non-invasive electrostatic doping. The nature of the superconducting order presents a recurring open question in this context. In this work, we quantitatively assess the case of spin-fluctuation-mediated pairing for $\Gamma$-valley twisted transition metal dichalcogenide homobilayers. We self-consistently and dynamically calculate the doping dependent superconducting transition temperature $T_{\mathrm{c}}$ revealing a superconducting dome with a maximal $T_{\mathrm{c}}\approx 0.1-1$ K depending on twist angle. We compare our results with conventional phonon-mediated superconductivity and identify clear fingerprints in the doping dependence of $T_{\mathrm{c}}$, which allow experiments to distinguish between different pairing mechanisms.