Switching Magnetism and Superconductivity with Spin-Polarized Current in Iron-Based Superconductor

Abstract

We have explored a new mechanism for switching magnetism and superconductivity in a magnetically frustrated iron-based superconductor using spin-polarized scanning tunneling microscopy (SPSTM). Our SPSTM study on single crystal Sr 2 VO 3 FeAs shows that a spin-polarized tunneling current can switch the Fe-layer magnetism into a non-trivial C 4 (2× 2) order, not achievable by thermal excitation with unpolarized current. Our tunneling spectroscopy study shows that the induced C 4 (2× 2) order has characteristics of plaquette antiferromagnetic order in Fe layer and strongly suppressed superconductivity. Also, thermal agitation beyond the bulk Fe spin ordering temperature erases the C 4 state. These results suggest a new possibility of switching local superconductivity by changing the symmetry of magnetic order with spin-polarized and unpolarized tunneling currents in iron-based superconductors.