(001) - √13⨯√13*

Bulk FeTe shows a bicollinear antiferromagnetic order under 65 K [1], but recent angle-resolved photoemission and scanning tunneling spectroscopy research also revealed a Kondo-like behavior in FeTe [2], showing that the ground state of FeTe is complicated. Our previous research showed that SrTiO₃(001)-√13⨯√13 substrate leads to a C₂ symmetry on monolayer (ML) FeSe, a cousin of FeTe; furthermore, we found that the electron doping from the SrTiO₃ surface locally modulates the superconducting gap size of ML FeSe [3]. These prompt several questions: 1. Can the SrTiO₃-√13⨯√13 substrate lower the rotational symmetry on the isostructural ML FeTe? 2. Can the Kondo behavior be confirmed on the ML FeTe? 3. Can the SrTiO₃ substrate locally modulate the ground state of ML FeTe?

To clarify the above points, we performed low-temperature scanning tunneling microscopy/spectroscopy (STM/STS, T: 5 K ~ 77 K) experiments on the ML FeTe/SrTiO₃-√13⨯√13.

Results [4]:

1. The STM data indicates a substrate-induced C₂ rotational symmetry on ML FeTe, similar to ML FeSe on SrTiO₃-√13⨯√13.

2. The STS spectra obtained on ML FeTe show Fano-line shape near the Fermi level, illustrating a Kondo scenario that localized Fe spins are screened by the conduction electrons.

3. Two types of Fano-line spectra were confirmed, and their spatial dependence follows the √13⨯√13 periodicities, indicating that the SrTiO₃ substrate can modulate the interaction between the localized spin and conduction electrons mentioned above.

Details will be given in the presentation.