TY - JOUR
T1 - Spin and Charge Interconversion in Dirac-Semimetal Thin Films
AU - Yanez, Wilson
AU - Ou, Yongxi
AU - Xiao, Run
AU - Koo, Jahyun
AU - Held, Jacob T.
AU - Ghosh, Supriya
AU - Rable, Jeffrey
AU - Pillsbury, Timothy
AU - Delgado, Enrique González
AU - Yang, Kezhou
AU - Chamorro, Juan
AU - Grutter, Alexander J.
AU - Quarterman, Patrick
AU - Richardella, Anthony
AU - Sengupta, Abhronil
AU - McQueen, Tyrel
AU - Borchers, Julie A.
AU - Mkhoyan, K. Andre
AU - Yan, Binghai
AU - Samarth, Nitin
N1 - Funding Information:
The principal support for this project was provided by SMART, one of seven centers of nCORE, a Semiconductor Research Corporation program, sponsored by the National Institute of Standards and Technology (NIST). This supported the synthesis and standard characterization of heterostructures as well as spin-charge interconversion measurements (WY, YO, NS) and their characterization using STEM (JH, SG, AM). Additional support for materials synthesis was provided by the Institute for Quantum Matter under DOE EFRC grant DE-SC0019331 (RX, JC, NS, TM). The Penn State Two-Dimensional Crystal Consortium-Materials Innovation Platform (2DCC-MIP) under NSF Grant No. DMR-1539916 provided support for ARPES measurements (YO, TP, AR, NS). The magnetometry measurements were carried out by JR, supported by a grant from the University of Chicago. Part of this work was carried out in the College of Science and Engineering Characterization Facility, University of Minnesota, which has received capital equipment funding from the National Science Foundation through the UMN MRSEC under Award Number DMR-2011401 (JH, SG, AM). EG acknowledges support for an undergraduate summer internship from the Office of Graduate Educational Equity Programs and Eberly College of Science at the Pennsylvania State University. B.Y. acknowledges the financial support by the European Research Council (ERC Consolidator Grant No. 815869). Certain commercial equipment, instruments, or materials (or suppliers, or software, etc.) are identified in this paper to foster understanding. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials or equipment identified are necessarily the best available for the purpose.
Publisher Copyright:
© 2021 American Physical Society.
PY - 2021/11
Y1 - 2021/11
N2 - 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.
AB - 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.
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U2 - 10.1103/PhysRevApplied.16.054031
DO - 10.1103/PhysRevApplied.16.054031
M3 - Article
AN - SCOPUS:85119966303
SN - 2331-7019
VL - 16
JO - Physical Review Applied
JF - Physical Review Applied
IS - 5
M1 - 054031
ER -