Low-temperature metal-insulator transition in the electron-doped iron chalcogenide FeSe superconductor

¹ Max-Planck-Institut für Chemische Physik fester Stoffe - 01187 Dresden, Germany, EU
² Technische Universität Dortmund, Lehrstuhl für Theoretische Physik I - 44221 Dortmund, Germany, EU

Received: 15 January 2010
Accepted: 7 July 2010

Abstract

The normal state of the iron chalcogenide superconductors shows a range of inexplicable features. Both bad metallic resistivity, characteristic pseudogap features and proximity to insulating states mark these systems as correlated non-Fermi liquid metals. Here, using the LDA+DMFT scheme with sizable multi-orbital correlations, we show how the incoherent non-Fermi liquid metallic state of tetragonal-FeSe superconductor is inherently unstable to the specific kind of insulator seen in experiments. We describe the metal-insulator transition in electron-doped FeSe microscopically, along with implications for the low-temperature specific heat and static spin susceptibility.