Quantum Phase Transition of Correlated Iron-Based Superconductivity in LiFe1-xCoxAs

Jia Xin Yin, Songtian S. Zhang, Guangyang Dai, Yuanyuan Zhao, Andreas Kreisel, Gennevieve Macam, Xianxin Wu, Hu Miao, Zhi Quan Huang, Johannes H.J. Martiny, Brian M. Andersen, Nana Shumiya, Daniel Multer, Maksim Litskevich, Zijia Cheng, Xian Yang, Tyler A. Cochran, Guoqing Chang, Ilya Belopolski, Lingyi XingXiancheng Wang, Yi Gao, Feng Chuan Chuang, Hsin Lin, Ziqiang Wang, Changqing Jin, Yunkyu Bang, M. Zahid Hasan

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


The interplay between unconventional Cooper pairing and quantum states associated with atomic scale defects is a frontier of research with many open questions. So far, only a few of the high-temperature superconductors allow this intricate physics to be studied in a widely tunable way. We use scanning tunneling microscopy to image the electronic impact of Co atoms on the ground state of the LiFe1-xCoxAs system. We observe that impurities progressively suppress the global superconducting gap and introduce low energy states near the gap edge, with the superconductivity remaining in the strong-coupling limit. Unexpectedly, the fully opened gap evolves into a nodal state before the Cooper pair coherence is fully destroyed. Our systematic theoretical analysis shows that these new observations can be quantitatively understood by the nonmagnetic Born-limit scattering effect in an s±-wave superconductor, unveiling the driving force of the superconductor to metal quantum phase transition.

Original languageEnglish (US)
Article number217004
JournalPhysical review letters
Issue number21
StatePublished - Nov 20 2019

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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