Strong correlations and spin-density-wave phase induced by a massive spectral weight redistribution in α-Fe1.06Te

The electronic structure of alpha-Fe1.06Te is studied with angle-resolved photoemission spectroscopy. We show that there is substantial spectral weight around Gamma and X, and line shapes are intrinsically broad in the paramagnetic state. The magnetic transition is characterized by a massive spectral weight transfer over an energy range as large as the bandwidth, which even exhibits a hysteresis loop that marks the strong first-order transition. Coherent quasiparticles emerge in the magnetically ordered state due to decreased spin fluctuations, which accounts for the change in transport properties from insulating behavior to metallic behavior. Our observation demonstrates that Fe1.06Te distinguishes itself from other iron-based systems with more local characters and much stronger interactions, and how a spin-density wave is formed in the presence of strong correlation.