Strong Correlation Between Superconductivity and Ferromagnetism in an Fe-Chalcogenide Superconductor

• Published in: Nano letters Vol. 21; no. 17; pp. 7277 - 7283
• Main Authors: McLaughlin, Nathan J, Wang, Hailong, Huang, Mengqi, Lee-Wong, Eric, Hu, Lunhui, Lu, Hanyi, Yan, Gerald Q, Gu, Genda, Wu, Congjun, You, Yi-Zhuang, Du, Chunhui Rita
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 08-09-2021
• Subjects: CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Nitrogen vacancy magnetometry; Quantum sensing; Topological superconductors; Unconventional ferromagnetism; Unconventional ferromagnetism; Nitrogen vacancy magnetometry; Quantum sensing; Topological superconductors
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.1c02424

The interplay among topology, superconductivity, and magnetism promises to bring a plethora of exotic and unintuitive behaviors in emergent quantum materials. The family of Fe-chalcogenide superconductors FeTe x Se1–x are directly relevant in this context due to their intrinsic topological band structure, high-temperature superconductivity, and unconventional pairing symmetry. Despite enormous promise and expectation, the local magnetic properties of FeTe x Se1–x remain largely unexplored, which prevents a comprehensive understanding of their underlying material properties. Exploiting nitrogen vacancy (NV) centers in diamond, here we report nanoscale quantum sensing and imaging of magnetic flux generated by exfoliated FeTe x Se1–x flakes, demonstrating strong correlation between superconductivity and ferromagnetism in FeTe x Se1–x . The coexistence of superconductivity and ferromagnetism in an established topological superconductor opens up new opportunities for exploring exotic spin and charge transport phenomena in quantum materials. The demonstrated coupling between NV centers and FeTe x Se1–x may also find applications in developing hybrid architectures for next-generation, solid-state-based quantum information technologies.