Spin-torque generation in topological insulator based heterostructures

Mark H. Fischer, Abolhassan Vaezi, Aurelien Manchon, Eun Ah Kim

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


Heterostructures utilizing topological insulators exhibit a remarkable spin-torque efficiency. However, the exact origin of the strong torque, in particular whether it stems from the spin-momentum locking of the topological surface states or rather from spin-Hall physics of the topological-insulator bulk, remains unclear. Here, we explore a mechanism of spin-torque generation purely based on the topological surface states. We consider topological-insulator-based bilayers involving ferromagnetic metal (TI/FM) and magnetically doped topological insulators (TI/mdTI), respectively. By ascribing the key theoretical differences between the two setups to location and number of active surface states, we describe both setups within the same framework of spin diffusion of the nonequilibrium spin density of the topological surface states. For the TI/FM bilayer, we find large spin-torque efficiencies of roughly equal magnitude for both in-plane and out-of-plane spin torques. For the TI/mdTI bilayer, we elucidate the dominance of the spin-transfer-like torque. However, we cannot explain the orders of magnitude enhancement reported. Nevertheless, our model gives an intuitive picture of spin-torque generation in topological-insulator-based bilayers and provides theoretical constraints on spin-torque generation due to topological surface states.

Original languageEnglish
Article number125303
JournalPhysical Review B
Issue number12
StatePublished - 11 Mar 2016

Bibliographical note

Publisher Copyright:
© 2016 American Physical Society.


Dive into the research topics of 'Spin-torque generation in topological insulator based heterostructures'. Together they form a unique fingerprint.

Cite this