Truncated unity functional renormalization group for multiband systems with spin-orbit coupling

TL;DR

This paper reviews the truncated-unity functional renormalization group (TU-fRG) method, extending it to multiband systems with spin-orbit coupling, aiming to improve predictions of ground states and energy scales in quantum materials.

Contribution

It introduces an extension of the TU-fRG method to multiband systems with spin-orbit coupling, enhancing its applicability to complex quantum materials.

Findings

Extended TU-fRG to multiband systems with spin-orbit coupling.

Discussed implementation aspects and future challenges.

Provided insights into predicting ground-state orderings.

Abstract

Although the functional renormalization group (fRG) is by now a well-established method for investigating correlated electron systems, it is still undergoing significant technical and conceptual improvements. In particular, the motivation to optimally exploit the parallelism of modern computing platforms has recently led to the development of the "truncated-unity" functional renormalization group (TU-fRG). Here, we review this fRG variant, and we provide its extension to multiband systems with spin-orbit coupling. Furthermore, we discuss some aspects of the implementation and outline opportunities and challenges ahead for predicting the ground-state ordering and emergent energy scales for a wide class of quantum materials.