//masumhabib.com/2015-08-09T01:49:00-07:002015-08-09T01:49:00-07:00K M Masum Habibtag:masumhabib.com,2015-08-09:blog/chiral-tunneling-of-topological-states-towards-the-efficient-generation-of-spin-current-using-spin-momentum-locking/

<p>Our research on topological insulator pn junction is published in Physical Review Letters. Given below is abstract. Full article can be found <a class="reference external" href="/pages/publications/articles/Habib_PRL15.pdf">here</a>.</p> <div class="figure"> <img alt="" src="//masumhabib.com/blog/chiral-tunneling-of-topological-states-towards-the-efficient-generation-of-spin-current-using-spin-momentum-locking/images/PRL15.png" /> </div> <div class="section" id="abstract"> <h2><em>Abstract</em></h2> <p>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.</p> </div>