Topological pn junction

Modern day electronic technology is widely based on semiconductor pn junctions. In this article we propose and calculate a lateral topological pn junction based on three dimensional topological insulator Bi₂Se₃. In a previous work, we showed how twin boundaries (a kind of inversion symmetry breaking planar defects) induce a spontaneous polarisation in Bi₂Se₃ which in turn generate a self doping of the topological surface states. In this work we exploit this feature along with surface Green's function matching techniques to calculate the electronic and transport properties of a lateral topological pn junction of Bi₂Se₃ with no extrinsic dopants.