Symmetry-Driven Spin-Wave Gap Modulation in Nanolayered SrRuO<sub>3</sub>/SrTiO<sub>3</sub> Heterostructures: Implications for Spintronic Applications
Seung Gyo Jeong, Hyeonbeom Kim, Sung Ju Hong, Dongseok Suh, Woo Seok Choi
Abstract
A strong correlation between magnetic interaction and topological symmetries leads to unconventional magneto-transport behavior. Weyl Fermions induce topologically protected spin-momentum locking, which is closely related to spin-wave gap formation in magnetic crystals. Ferromagnetic SrRuO 3, regarded as a strong candidate for Weyl semimetal, inherently possesses a nonzero spin-wave gap due to its strong magnetic anisotropy. In this paper, we propose a method to control the spin-wave dynamics by nanolayer designing of the SrRuO 3 /SrTiO 3 superlattices. In particular, the six-unit-cell-thick SrRuO 3 layers within the superlattices undergo a phase transition in crystalline symmetry from orthorhombic to tetragonal, as the thickness of the SrTiO 3 layers is modulated with atomic-scale precision. Consequently, the magnetic anisotropy, anomalous Hall conductivity, and spin-wave gap could be systematically manipulated. Such customization of magnetic anisotropy via nanoscale heterostructuring offers a novel control knob to tailor the magnon excitation energy for future spintronic applications, including magnon waveguides and filters. Our nanolayer approach unveils the important correlation between the tunable lattice degrees of freedom and spin dynamics in topologically nontrivial magnetic materials.