Evidence of spin and charge density waves in Chromium electronic bands

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The incommensurate spin density wave (SDW) of Chromium represents the classic example of itinerant antiferromagnetism induced by the nesting of the Fermi surface, which is further enriched by the co-presence of a charge density wave (CDW). Here, we explore its electronic band structure using soft-X-ray angle-resolved photoemission spectroscopy (ARPES) for a proper bulk-sensitive investigation. We find that the long-range magnetic order gives rise to a very rich ARPES signal, which can only be interpreted with a proper first-principles description of the SDW and CDW, combined with a band unfolding procedure, reaching a remarkable agreement with experiments. Additional features of the SDW order are obscured by superimposed effects related to the photoemission process, which, unexpectedly, are not predicted by the free-electron model for the final states. We demonstrate that, even for excitation photon energies up to 1 keV, a multiple scattering description of the photoemission final states is required.