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

Research output: Contribution to journalArticlepeer-review

90 Scopus citations

Abstract

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
Volume117
Issue number7
DOIs
StatePublished - Aug 11 2016

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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