2016/08/02 by Seokhwan Choi, Won-Jun Jang, Choi, Seokhwan +26 · 1 citation
Materials Science · Physics and Astronomy · #Antiferromagnetism #Condensed matter physics #Electronic and Structural Properties of Oxides #FOS: Physical sciences #Ground state #Iron-based superconductors research #Magnetic moment #Magnetism #Phase (matter) #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Spin (aerodynamics) #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity #Superconductivity (cond-mat.supr-con) #Tetragonal crystal system #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.1608.00884
openalex publication_date 2016/08/02 · arxiv created 2017/06/19 · arxiv updated 2017/06/20 · openalex created_date 2017/07/14 · openalex updated_date 2026/07/28
The symmetry requirement and the origin of magnetic orders coexisting with superconductivity have been strongly debated issues of iron-based superconductors (FeSCs). Observation of C4-symmetric antiferromagnetism in violation of the inter-band nesting condition of spin-density waves in superconducting ground state will require significant change in our understanding of the mechanism of FeSC. The superconducting material Sr2VO3FeAs, a bulk version of monolayer FeSC in contact with a perovskite layer with its magnetism (TN ~ 50 K) and superconductivity (Tc ~ 37 K) coexisting at parent state, has no reported structural orthorhombic distortion and thus makes a perfect system to look for theoretically expected C4 magnetisms. Based on variable temperature spin-polarized scanning tunneling microscopy (SPSTM) with newly discovered imaging mechanism that removes the static surface reconstruction (SR) pattern by fluctuating it rapidly with spin-polarized tunneling current, we could visualize underlying C4 symmetric (2×2) magnetic domains and its phase domain walls. We find that this magnetic order is perfectly consistent with the plaquette antiferromagnetic order in tetragonal Fe spin lattice expected from theories based on the Heisenberg exchange interaction of local Fe moments and the quantum order by disorder. The inconsistency of its modulation Q vectors from the nesting condition also implies that the nesting-based C2 symmetric magnetism is not a unique prerequisite of high-Tc FeSC. Furthermore, the plaquette antiferromagnetic domain wall dynamics under the influence of small spin torque effect of spin-polarized tunneling current are shown to be consistent with theoretical simulation based on the extended Landau-Lifshitz-Gilbert equation.