Intrinsic Strain-Driven Topological Evolution in SrRuO3 via Flexural Strain Engineering

Abstract: Strain engineering offers a powerful route to tailor topological electronic structures in correlated oxides, yet conventional epitaxial strain approaches introduce extrinsic factors such as substrate-induced phase transitions and crystalline quality variations, which makes the unambiguous identification of the intrinsic strain effects challenging. Here, we develop a flexural strain platform based on van der Waals epitaxy and flexible micro-fabrication, enabling precise isolation and quantification of intrinsic strain effects on topological electronic structures in correlated oxides without extrinsic interference. Through strain-dependent transport measurements of the Weyl semimetal SrRuO3, we observed a significant enhancement of anomalous Hall conductivity by 21% under a tiny strain level of 0.2%, while longitudinal resistivity remains almost constant -- a hallmark of intrinsic topological response. First-principles calculations reveal a distinct mechanism where strain-driven non-monotonic evolution of Weyl nodes across the Fermi level, exclusively governed by lattice constant modulation, drives the striking AHC behavior. Our work not only highlights the pivotal role of pure lattice strain in topological regulation but also establishes a universal platform for designing flexible topological oxide devices with tailored functionalities.