Quantum Phase Transition of Correlated Iron-Based Superconductivity in LiFe1-xCoxAs
- Quantum Phase Transition of Correlated Iron-Based Superconductivity in LiFe1-xCoxAs
- BANG, YUNKYU
- Date Issued
- American Physical Society
- 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.
- Arsenic compounds; Ground state; Iron; Iron compounds; Lithium compounds; Phase transitions; Quantum theory; Scanning tunneling microscopy; Atomic-scale defects; Electronic impact; Low-energy state; Quantum phase transitions; Scattering effects; Strong coupling; Superconducting gaps; Wave superconductors; Iron-based Superconductors
- Article Type
- Physical Review Letters, vol. 123, no. 21, page. 217004 - 217004, 2019-11
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