Quantum chemical formulation of high-Tc superconductivity applied to α-FeSe

Journal article, 2010

High-Tc superconductivity (HTS) in the cuprates is revisited and employed to interpret the superconductivity phenomenon in α-FeSe. HTS in α-FeSe is proposed to emerge from accidental near degeneracy among spin zero Fe2+ states on a magnetic sublattice in a magnetically inhomogeneous reference state illustrated by density-functional theory calculations. The spin zero Fe2+ ions sublattice is embedded in a second sublattice, which displays antiferromagnetic order. Existence of the latter enforces the former, and causes the violation of Hund´s rule. Detailed contact with the conceptual understanding of superconductivity in the cuprates is made.