Dislocation Majorana zero modes in perovskite oxide 2DEG

Abstract

Much of the current experimental efforts for detecting Majorana zero modes have been centered on probing the boundary of quantum wires with strong spin-orbit coupling. The same type of Majorana zero mode can also be realized at crystalline dislocations in 2D superconductors with the nontrivial weak topological indices. Unlike at an Abrikosov vortex, at such a dislocation, there are no other low-lying midgap states than the Majorana zero mode so that it avoids usual complications encountered in experimental detections such as scanning tunneling microscope (STM) measurements. We will show that, using the anisotropic dispersion of the $t_{2g}$ orbitals of Ti or Ta atoms, such a weak topological superconductivity can be realized when the surface 2DEG of SrTiO$_3$ or KTaO$_3$ becomes superconducting, which can occur through either intrinsic pairing or proximity to existing s-wave superconductors.