We explore 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 Sr2VO3FeAs shows that a spin-polarized tunneling current can switch the Fe-layer magnetism into a nontrivial C4 (2×2) order, which cannot be achieved by thermal excitation with an unpolarized current. Our tunneling spectroscopy study shows that the induced C4 (2×2) order has characteristics of plaquette antiferromagnetic order in the Fe layer and strongly suppresses superconductivity. Also, thermal agitation beyond the bulk Fe spin ordering temperature erases the C4 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.
Bibliographical noteFunding Information:
The authors are thankful for helpful discussions with A. Chubukov, I. Mazin, H.-J. Lee, S.-J. Kahng, Ja-Yong Koo, C. Kim, J. J. Yu, W. Wu, K.-J. Kim, and J. H. Shim. This work was supported by National Research Foundation (NRF) through the Pioneer Research Center Program (No. 2013M3C1A3064455), the Basic Science Research Programs (No. 2017R1D1A1B01016186), SRC Center for Topological Matter (No. 2011-0030785), the Creative Research Initiative Program (No. 2011-0018306), the Max Planck POSTECH/KOREA Research Initiative Program (No. 2016K1A4A4A01922028), and the Brain Korea 21 PLUS Project of Korea Government. It is also supported by IBS-R017-D1 and IBS-R027-D1 and by Korea Research Institute of Standards and Science through the Metrology Research Center Program funded (No. 2015-15011069), by MSIP of Korea through NRF (2015R1C1A1A01052411), by the Samsung Advanced Institute of Technology (SAIT), and by the Gordon and Betty Moore Foundation’s EPiQS Initiative through Grant No. GBMF4413 to the Rutgers Center for Emergent Materials. Computational resources have been provided by KISTI Supercomputing Center (Project No. KSC-2016-C3-0052).
© 2017 American Physical Society.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)