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arXiv · 1707.01191

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

Seokhwan Choi·Hyoung Joon Choi·Jong Mok Ok·Yeonghoon Lee·Won-Jun Jang·Alex Taekyung Lee·Young Kuk·SungBin Lee·Andreas J. Heinrich·Sang-Wook Cheong·Yunkyu Bang·Steven Johnston·Jun Sung Kim·Jhinhwan Lee
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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$\times$2) order, not achievable by thermal excitation with unpolarized current. Our tunneling spectroscopy study shows that the induced $C_4$ (2$\times$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.

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Seokhwan Choi, Hyoung Joon Choi, Jong Mok Ok, Yeonghoon Lee, Won-Jun Jang, Alex Taekyung Lee, Young Kuk, SungBin Lee, Andreas J. Heinrich, Sang-Wook Cheong, Yunkyu Bang, Steven Johnston, Jun Sung Kim, Jhinhwan Lee. 2017-09-14. Switching Magnetism and Superconductivity with Spin-Polarized Current in Iron-Based Superconductor. https://doi.org/10.1103/physrevlett.119.227001

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