[PC8] Nickelates, Iron-based

4:30 PM - 4:45 PM JST(7:30 AM - 7:45 AM UTC)

[PC8-06] Higher-order epitaxy: A pathway to suppressing structural instability and emergent superconductivity

*Yuki Sato¹, Soma Nagahama², Shunsuke Kitou³, Hajime Sagayama⁴, Ilya Belopolski¹, Ryutaro Yoshimi^1,3, Minoru Kawamura¹, Atsushi Tsukazaki^2,5, Naoya Kanazawa⁶, Takuya Nomoto⁷, Ryutaro Arita^1,8, Taka-hisa Arima^1,3, Masashi Kawasaki^1,2, Yoshinori Tokura^1,2,9 (1. RIKEN Center for Emergent Matter Science (CEMS) (Japan), 2. Department of Applied Physics and Quantum-phase Electronics Center, University of Tokyo (Japan), 3. Department of Advanced Materials Science, University of Tokyo (Japan), 4. Institute of Materials Structure Science, High Energy Accelerator Research Organization (Japan), 5. Institute for Materials Research, Tohoku University (Japan), 6. Institute of Industrial Science, University of Tokyo (Japan), 7. Department of Physics, Tokyo Metropolitan University (Japan), 8. Department of Physics, University of Tokyo (Japan), 9. Tokyo College, University of Tokyo (Japan))

Keywords:

Molecular beam epitaxy,moire superlattice,iron-based superconductor

Molecular beam epitaxy enables the growth of thin film materials with novel properties and functionalities. Typically, the lattice constants of films and substrates are designed to match to minimize disorders and strains. However, significant lattice mismatches can result in higher-order epitaxy, where commensurate growth occurs with a period defined by integer multiples of the lattice constants. Despite its potential, higher-order epitaxy is rarely used to enhance material properties or induce emergent phenomena. Here, we report single-crystalline FeTe films grown via 6:5 commensurate higher-order epitaxy on CdTe(001) substrates. Scanning transmission electron microscopy reveals self-organized periodic interstitials near the interface, arising from higher-order lattice matching (Figure 1). Additionally, synchrotron x-ray diffraction shows that the tetragonal-to-monoclinic structural transition in bulk FeTe is strongly suppressed. Remarkably, these films exhibit substrate-selective two-dimensional superconductivity, likely due to suppressed monoclinic distortion. These findings demonstrate the potential of higher-order epitaxy as a tool to control materials and inducing emergent phenomena.