Coexistence of two order parameters and a pseudogaplike feature in the iron-based superconductor LaFeAsO1-xFx
SCIE
SCOPUS
- Title
- Coexistence of two order parameters and a pseudogaplike feature in the iron-based superconductor LaFeAsO1-xFx
- Authors
- Gonnelli, RS; Daghero, D; Tortello, M; Ummarino, GA; Stepanov, VA; Kim, JS; Kremer, RK
- Date Issued
- 2009-05
- Publisher
- American Physical Society
- Abstract
- The nature and value of the order parameters (OPs) in the superconducting Fe-based oxypnictides REFeAsO1-xFx (RE=rare earth) are a matter of intense debate, also connected to the pairing mechanism which is probably unconventional. Point-contact Andreev-reflection experiments on LaFeAsO1-xFx gave us direct evidence of three energy scales in the superconducting state: a nodeless superconducting OP, Delta(1)=2.8-4.6 meV, which scales with the local T-c of the contact; a larger unconventional OP that gives conductance peaks at 9.8-12 meV, apparently closes below T-c and decreases on increasing the T-c of the contact; a pseudogaplike feature (i.e., a depression in the conductance around zero bias) that survives in the normal state up to T-*similar to 140 K (close to the Neel temperature of the undoped compound), which we associate to antiferromagnetic spin fluctuations coexisting with superconductivity. These findings point toward a complex, unconventional nature of superconductivity in LaFeAsO1-xFx.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/12199
- DOI
- 10.1103/PhysRevB.79.184526
- ISSN
- 1098-0121
- Article Type
- Article
- Citation
- PHYSICAL REVIEW B, vol. 79, no. 18, 2009-05
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