First-Principles Correlated Approach to the Normal State of Strontium Ruthenate

TL;DR

This paper uses a first-principles correlated approach to analyze the normal state of Sr₂RuO₄, revealing the role of multi-orbital charge fluctuations as a potential pairing mechanism for its unconventional superconductivity.

Contribution

It provides a unified, quantitative description of Sr₂RuO₄'s normal state and highlights the importance of multi-orbital charge fluctuations in its superconductivity.

Findings

Normal state responses are explained by a correlated first-principles approach.

Multi-orbital charge fluctuations are identified as a primary pairing glue.

Connection established between normal state behavior and superconductivity.

Abstract

The interplay between multiple bands, sizable multi-band electronic correlations and strong spin-orbit coupling may conspire in selecting a rather unusual unconventional pairing symmetry in layered Sr$_{2}$RuO$_{4}$. This mandates a detailed revisit of the normal state and, in particular, the $T$-dependent incoherence-coherence crossover. Using a modern first-principles correlated view, we study this issue in the actual structure of Sr$_{2}$RuO$_{4}$ and present a unified and quantitative description of a range of unusual physical responses in the normal state. Armed with these, we propose that a new and important element, that of dominant multi-orbital charge fluctuations in a Hund's metal, may be a primary pair glue for unconventional superconductivity. Thereby we establish a connection between the normal state responses and superconductivity in this system.