Electrically controllable zero-energy states in Rashba oxide heterostructure with in-plane magnetic field cooling

Abstract

Zero-energy states in tunnel spectra, an important manifestation of topological superconductivity, have been the focus of the field of topological phases of matter. However, experimentally creating and controlling the zero-energy states is difficult, e.g., it requires a large magnetic field in the case of topological superconductivity. Here, we report on an effective approach to generate controllable zero-energy states in the superconducting Rashba oxide heterostructure by in-plane magnetic field cooling. A pronounced zero-bias conductance peak emerging below a threshold magnetic field down to zero after in-plane magnetic field cooling of a Rashba perovskite oxide heterostructure connecting to an s-wave superconductor. We further demonstrate the high tunability of the zero-energy states between a zero-bias conductance peak and a zero-bias conductance valley by electrical gating at a zero magnetic field. Our theoretical analysis indicates that the in-plane magnetic field or magnetization could lead to finite center-of-mass momentum pairing that supports topological zero-energy states in the Rashba system and provides an opportunity to manipulate topological zero-energy states through gating.