Chiral tunneling of topological states: towards the efficient generation of spin current using spin-momentum locking

We show that the interplay between chiral tunneling and spin-momentum locking of helical surface states leads to spin amplification and filtering in a 3D topological insulator (TI). Our calculations show that the chiral tunneling across a TI pn junction allows normally incident electrons to transmit...

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Bibliographic Details
Published inPhysical review letters Vol. 114; no. 17; p. 176801
Main Authors Habib, K M Masum, Sajjad, Redwan N, Ghosh, Avik W
Format Journal Article
LanguageEnglish
Published United States 01.05.2015
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Summary:We show that the interplay between chiral tunneling and spin-momentum locking of helical surface states leads to spin amplification and filtering in a 3D topological insulator (TI). Our calculations show that the chiral tunneling across a TI pn junction allows normally incident electrons to transmit, while the rest are reflected with their spins flipped due to spin-momentum locking. The net result is that the spin current is enhanced while the dissipative charge current is simultaneously suppressed, leading to an extremely large, gate-tunable spin-to-charge current ratio (∼20) at the reflected end. At the transmitted end, the ratio stays close to 1 and the electrons are completely spin polarized.
ISSN:1079-7114
DOI:10.1103/PhysRevLett.114.176801