The Stoichiometry of FeSe

Abstract

Tetragonal iron selenide, FeSe, the layered parent compound of the recently discovered superconducting arsenide family, has previously been shown to be non magnetic and superconducting with a critical temperature near 8 K. There has, however, been a lack of consensus as to whether selenium vacancies present due to large deviations from ideal stoichiometry are required to give rise to the superconductivity. Here we describe the results of experiments that demonstrate simply that superconducting iron selenide can only be synthesized as a pure material when near stoichiometric (i.e. FeSe). Significant selenium deficiency or excess gives rise to secondary magnetic phases, and a suppression of the superconductivity.

References in corpus (5)

• Extreme Sensitivity of Superconductivity to Stoichiometry in FeSe (Fe1+dSe)
• Crystal structure of the new FeSe1-x superconductor
• Magnetism Driven by Anion Vacancies in Superconducting $\alpha$--FeSe${}_{1-x}$
• Neutron scattering Measurements of the phonon density of states of FeSe${}_{1-x}$ superconductors
• Electronic Structure of Superconducting FeSe Studied by High-Resolution Photoemission Spectroscopy