Surface-State-Dominated Spin-Charge Current Conversion in Topological-Insulator-Ferromagnetic-Insulator Heterostructures

Hailong Wang, James Kally, Joon Sue Lee, Tao Liu, Houchen Chang, Danielle Reifsnyder Hickey, K. Andre Mkhoyan, Mingzhong Wu, Anthony Richardella, Nitin Samarth

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155 Scopus citations


We report the observation of ferromagnetic resonance-driven spin pumping signals at room temperature in three-dimensional topological insulator thin films - Bi2Se3 and (Bi,Sb)2Te3 - deposited by molecular beam epitaxy on Y3Fe5O12 thin films. By systematically varying the Bi2Se3 film thickness, we show that the spin-charge conversion efficiency, characterized by the inverse Rashba-Edelstein effect length (λIREE), increases dramatically as the film thickness is increased from two quintuple layers, saturating above six quintuple layers. This suggests a dominant role of surface states in spin and charge interconversion in topological-insulator-ferromagnet heterostructures. Our conclusion is further corroborated by studying a series of Y3Fe5O12/(Bi,Sb)2Te3 heterostructures. Finally, we use the ferromagnetic resonance linewidth broadening and the inverse Rashba-Edelstein signals to determine the effective interfacial spin mixing conductance and λIREE.

Original languageEnglish (US)
Article number076601
JournalPhysical review letters
Issue number7
StatePublished - Aug 11 2016

Bibliographical note

Funding Information:
The work at Penn State, Colorado State, and University of Minnesota is supported by the Center for Spintronic Materials, Interfaces, and Novel Architectures (C-SPIN), a funded center of STARnet, a Semiconductor Research Corporation (SRC) program sponsored by MARCO and DARPA. N.S. and A.R. acknowledge additional support from ONR- N00014-15-1-2364. T.L., H.C., and M.W. acknowledge additional support from NSF-ECCS-1231598 and ARO-W911NF-14-1-0501. This work utilized (1) the College of Science and Engineering (CSE) Characterization Facility, University of Minnesota (UM), supported in part by NSF through the UMN MRSEC program (No. DMR-1420013); and (2) the CSE Minnesota Nano Center, UM, supported in part by NSF through the NNIN program.

Publisher Copyright:
© 2016 American Physical Society.

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