# Berry phase manipulation in ultrathin SrRuO$_3$ films

## TL;DR

This paper demonstrates how disorder influences the Berry phase and anomalous Hall effect in ultrathin SrRuO$_3$ films, providing experimental and numerical evidence that challenges the topological Hall effect attribution in these materials.

## Contribution

It reveals the tunability of the Berry phase via disorder effects in ultrathin SrRuO$_3$ films and clarifies the origin of the anomalous Hall effect in these systems.

## Key findings

- Disorder affects the intrinsic Berry phase contribution to AHE.
- Experimental evidence supports a multi-channel AHE scenario.
- Challenges the attribution of the topological Hall effect to spin textures.

## Abstract

A notion of the Berry phase is a powerful means to unravel the non-trivial role of topology in various novel phenomena observed in chiral magnetic materials and structures. A celebrated example is the intrinsic anomalous Hall effect (AHE) driven by the non-vanishing Berry phase in the momentum space. As the AHE is highly dependent on details of the band structure near the Fermi edge, the Berry phase and AHE can be altered in thin films whose chemical potential is tunable by dimensionality and disorder. Here, we demonstrate that in ultrathin SrRuO$_3$ films the Berry phase can be effectively manipulated by the effects of disorder on the intrinsic Berry phase contribution to the AHE, which is corroborated by our numerically exact calculations. In addition, our findings provide ample experimental evidence for the superficial nature of the topological Hall effect attribution to the protected spin texture and instead lend strong support to the multi-channel AHE scenario in ultrathin SrRuO$_3$.