Superconductivity and its mechanism in an ab initio model for electron-doped LaFeAsO

• Published in: Nature communications 2014-12, Vol.5 (1), p.5738-5738, Article 5738
• Main Authors: Misawa, Takahiro, Imada, Masatoshi
• Format: Article
• Language: English
• Subjects: 639/301/119/1003; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms6738

Two families of high-temperature superconductors whose critical temperatures are higher than 50 K are known. One are the copper oxides and the other are the iron-based superconductors. Comparisons of mechanisms between these two in terms of common ground as well as distinctions will greatly help in searching for higher T c superconductors. However, studies on mechanisms for the iron family based on first principles calculations are few. Here we first show that superconductivity emerges in the state-of-the-art numerical calculations for an ab initio multi-orbital model of an electron-doped iron-based superconductor LaFeAsO, in accordance with experimental observations. Then the mechanism of the superconductivity is identified as enhanced uniform density fluctuations by one-to-one correspondence with the instability towards inhomogeneity driven by first-order antiferromagnetic and nematic transitions. Despite many differences, certain common features with the copper oxides are also discovered in terms of the underlying orbital-selective Mottness found in the iron family. Understanding unconventional superconductivity is a challenge in condensed matter physics. Ab initio calculations by Takahiro Misawa and Masatoshi Imada reproduce many experimental features of the iron-based superconductor LaFeAsO, and suggest the mechanism is mediated by electron density fluctuations.