# Correlation tuned Fermi-arc topology in a Weyl ferromagnet

## TL;DR

This study demonstrates that tuning electronic correlation strength in Co3Sn2S2 effectively controls the topology and connectivity of Fermi arcs, revealing a topological change with stronger correlations and advancing manipulation of Weyl semimetals.

## Contribution

The paper shows that electronic correlations can be used to manipulate Fermi-arc topology in Weyl semimetals, supported by combined DFT+DMFT calculations and experimental data.

## Key findings

- Electronic correlation renormalizes bands and modifies Weyl points.
- FAs connect different Weyl points depending on correlation strength.
- Topological change of FAs observed with increased correlation.

## Abstract

Electrons on Fermi arcs (FAs), a hallmark of Weyl semimetals, exhibit chiral transport harboring chiral anomaly, negative magnetoresistance, and Majorana zero modes. While FAs were observed in exemplary Weyl semimetal TaAs and Co3Sn2S2, the manipulation of FAs has been rarely explored. Here we take Co3Sn2S2 as an example and demonstrate that tuning the electronic correlation strength is an effective way to control the topology and connectivity of FAs. After achieving a good agreement with experimentally measured band structure by employing combined density functional theory and dynamical mean field theory (DFT+DMFT) calculations, we show that the experimental charge dynamics are well reproduced by DFT+DMFT calculations but not DFT calculations. Electronic correlation renormalizes the bands around the Fermi level and modifies the energy and location of Weyl points, and the resulting FAs. In particular, on the Co-terminated surface, the FAs are formed by connecting Weyl points located in adjacent Brillouin zones in DFT+DMFT calculations and experiments, in strong contrast to the FAs connecting Weyl points within the same Brillouin zone in DFT calculations. We further show the evolution of FAs with correlation and reveal a topological change of the FAs on the Sn-terminated surface at stronger correlation strength. Our study sheds new light on experimental manipulation of FAs to improve the electronic properties of correlated Weyl semimetals.