Our research on topological insulator pn junction is published in Physical Review Letters. Given below is abstract. Full article can be found here.
![](http://masumhabib.com/blog/chiral-tunneling-of-topological-states-towards-the-efficient-generation-of-spin-current-using-spin-momentum-locking/images/PRL15.png)
Abstract
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.
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