Non-reciprocity as a probe of exotic quantum many-body states in iron-based superconductors

The interplay of broken inversion symmetry, magnetic order, electronic nematicity and superconducting instability is expected to drive exotic electronic states, such as spin-triplet pairing, nematic superconductivity, and Majorana edge mode. Materials with neither inversion nor time reversal symmetry are also subject to exhibit non-reciprocal transport phenomena, where currents flowing forward and backward are inequivalent. Although such effect has been investigated in mostly 2-dimensional polar superconductors, it remains little explored whether it can be found in a system where time reversal symmetry is broken through the proximity effect from an adjacent ferromagnetic material. Here by using novel MBE synthesis techniques, we develop epitaxial interface of ferromagnet and iron-based superconductors such as Fe(Se,Te). We show how non-reciprocity found in our devices reflects exotic quantum many-body states in iron-based superconductors.