Meissner Effect in Iron Chalcogenide-Based Heterostructures

Recent studies have highlighted the intriguing phenomenon of interface-induced superconductivity in iron chalcogenide-based heterostructures. The combination of two non-superconducting materials can lead to superconductivity at the interface with a critical temperature (T_c) around 10 K. However, the underlying mechanisms of this superconductivity remain unclear. Existing reports primarily confirm superconductivity through zero resistance measurements [1-3], while another crucial characteristic, the Meissner effect, has received less attention. In this talk, we will utilize cryogenic magnetic force microscopy (MFM) to observe the Meissner effect below T_c. By detecting the MFM signal as a function of tip-sample separation (z), we can demonstrate the repulsive force resulting from Meissner response. Additionally, through temperature-variable experiments, we will determine the sample's T_c based on the Meissner effect and compare it with in-situ transport measurements. This approach provides strong support of the emergent superconductivity in these heterostructures.



[1] Q. L. He et al. Nat. Commun. 5, 4247 (2014).

[2] J. Liang et al. PNAS 117, 221-227 (2020).

[3] H. Yi et al. Science 383, 634-639 (2024).