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Two-dome structure in electron-doped iron arsenide superconductors
Soshi Iimura1, Satoru Matsuishi, Satoru Matuishi
1Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan.
Nature Communications
|July 12, 2012
Summary
Researchers doped LaFeAsO with hydrogen to access new superconducting states. This study reveals a second superconducting dome in iron arsenide superconductors, reaching higher critical temperatures (T(c)).
Area of Science:
- Condensed Matter Physics
- Materials Science
- Superconductivity
Background:
- Iron arsenide superconductors like LaFeAsO(1-x)F(x) exhibit superconductivity via electron doping.
- Fluorine doping is limited by poor solubility, preventing access to over-doped regions.
Purpose of the Study:
- To overcome fluorine solubility limitations in LaFeAsO(1-x)F(x) superconductors.
- To explore superconductivity in hydrogen-doped LaFeAsO(1-x)H(x) and map its phase diagram.
Main Methods:
- Synthesized hydrogen-doped LaFeAsO(1-x)H(x) samples.
- Investigated the phase diagram up to x=0.53.
- Performed density functional theory (DFT) calculations.
Main Results:
- Discovered a second superconducting dome in LaFeAsO(1-x)H(x) for 0.21
- Achieved a maximum T(c) of 36 K at x=0.3, exceeding previous limits.
- DFT calculations showed Fe 3d band degeneracy at x=0.36, correlating with high T(c).
Conclusions:
- Hydrogen doping successfully expands the accessible phase diagram of iron arsenide superconductors.
- Band degeneracy, not Fermi surface nesting, appears crucial for inducing high-temperature superconductivity in this system.
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