• Yanez, Wilson
• Xiao, Run
• Mcqueen, Tyrel
• Samarth, Nitin
• Mkhoyan, K. Andre
• Held, Jacob T.
• Ou, Yongxi
• Borchers, Julie A.
• Richardella, Anthony
• Sengupta, Abhronil
• Yang, Kezhou
• Grutter, Alexander J.
• Quarterman, Patrick
• Yan, Binghai
• Pillsbury, Timothy
• Delgado, Enrique González
• Chamorro, Juan
• Rable, Jeffrey
• Koo, Jahyun

Abstract

<p>We use spin torque ferromagnetic resonance and ferromagnetic-resonance-driven spin pumping to detect spin-charge interconversion at room temperature in heterostructure devices that interface an archetypal Dirac semimetal, Cd3As2, with a metallic ferromagnet, Ni0.80Fe0.20 (permalloy). Angle-resolved photoemission directly reveals the Dirac-semimetal nature of the samples prior to device fabrication and high-resolution transmission electron microscopy is used to characterize the crystalline structure and the relevant heterointerfaces. We find that the spin-charge interconversion efficiency in Cd3As2/permalloy heterostructures is comparable to that in heavy metals and that it is enhanced by the presence of an interfacial oxide. Spin torque ferromagnetic resonance measurements reveal an in-plane spin polarization regardless of an oxidized or pristine interface. We discuss the underlying mechanisms for spin-charge interconversion by comparing our results with first principles calculations and conclude that extrinsic mechanisms dominate the observed phenomena. Our results indicate a need for caution in interpretations of spin-transport and spin-charge conversion experiments in Cd3As2 devices that seek to invoke the role of topological Dirac and Fermi arc states.</p>

Topics

• impedance spectroscopy
• experiment
• thin film
• transmission electron microscopy
• interfacial
• spin polarization