Nonlinear and Nonreciprocal Transport Effects in Untwinned Thin Films of Ferromagnetic Weyl Metal SrRuO3
Journal
Physical Review X
Journal Volume
14
Journal Issue
1
Start Page
011022
ISSN
2160-3308
Date Issued
2024-02-20
Author(s)
Uddipta Kar
Elisha Cho-Hao Lu
Akhilesh Kr. Singh
P. V. Sreenivasa Reddy
Youngjoon Han
Xinwei Li
Cheng-Tung Cheng
Song Yang
Chun-Yen Lin
Chia-Hung Hsu
David Hsieh
Wei-Cheng Lee
Wei-Li Lee
Abstract
The identification of distinct charge transport features, deriving from nontrivial bulk band and surface states, has been a challenging subject in the field of topological systems. In topological Dirac and Weyl semimetals, nontrivial conical bands with Fermi-arc surface states give rise to negative longitudinal magnetoresistance due to chiral anomaly effect and unusual thickness dependent quantum oscillation from Weyl-orbit effect, which were demonstrated recently in experiments. In this work, we report the experimental observations of large nonlinear and nonreciprocal transport effects for both longitudinal and transverse channels in an untwinned Weyl metal of SrRuO3 thin film grown on a SrTiO3 substrate. From rigorous measurements with bias current applied along various directions with respect to the crystalline principal axes, the magnitude of nonlinear Hall signals from the transverse channel exhibits a simple sinα dependence at low temperatures, where α is the angle between bias current direction and orthorhombic [001]o, reaching a maximum when current is along orthorhombic [11¯0]o. On the contrary, the magnitude of nonlinear and nonreciprocal signals in the longitudinal channel attains a maximum for bias current along [001]o, and it vanishes for bias current along [11¯0]o. The observed α-dependent nonlinear and nonreciprocal signals in longitudinal and transverse channels reveal a magnetic Weyl phase with an effective Berry curvature dipole along [11¯0]o from surface states, accompanied by 1D chiral edge modes along [001]o.
Publisher
American Physical Society (APS)
Type
journal article