Correspondence between Andreev reflection and Klein tunneling in bipolar graphene

Abstract

The Andreev reflection at a superconductor and the Klein tunneling through an n−p junction in graphene are two processes that couple electrons to holes—the former through the superconducting pair potential Δ and the latter through the electrostatic potential U. We derive that the energy spectra in the two systems are identical at low energies ε⪡Δ and for an antisymmetric potential profile U(−x,y)=−U(x,y). This correspondence implies that bipolar junctions in graphene may have zero density of states at the Fermi level and carry a current in equilibrium, analogous to the superconducting Josephson junctions. It also implies that nonelectronic systems with the same band structure as graphene, such as honeycomb-lattice photonic crystals, can exhibit pseudosuperconducting behavior.

Similar papers