Bulk sensitive photoelectron spectroscopy with soft and hard X-rays: Soft X-ray ARPES toward high resolution HAXPES

Soft and hard X-ray photoelectron spectroscopy (SX- and HAXPES) has been performed for strongly correlated transition-metal oxides and rare-earth compounds in order to reveal the bulk electronic structures and/or the bulk Fermi surfaces. The variation of the bulk V 3 d spectrum for Sr 1 - x Ca x VO 3 depending on x and the feature of the Fermi surfaces for Sr 2 - x Ca x RuO 4 is consistent with other bulk-sensitive measurements and band structure calculations, respectively. It has been demonstrated for rare-earth compounds that the application of the HAXPES enables us to obtain more reliable information on the bulk electronic structures and valences.