High-energy angle-resolved photoemission spectroscopy probing bulk correlated electronic states in quasi-one-dimensional ${\mathrm{V}}_6{\mathrm{O}}_{13}$ and $\mathrm{Sr}\mathrm{Cu}{\mathrm{O}}_2$

Soft x-ray excited angle-resolved photoemission spectroscopy (ARPES) is performed for the valence bands of quasi-one-dimensional ${\mathrm{V}}_6{\mathrm{O}}_{13}$ and $\mathrm{Sr}\mathrm{Cu}{\mathrm{O}}_2$ in order to reveal behavior of the strongly correlated $\mathrm{V}3d$ and $\mathrm{Cu}3d$ states. The resonance enhancement of the $\mathrm{V}3d$ state for the $\mathrm{V}2p$ core excitation and the high photoionization cross section of the $\mathrm{Cu}3d$ states compared with the $\mathrm{O}2p$ states are fully utilized in addition to the high resolutions in energy and momentum facilitated by recent instrument developments. Clear differences from the results of low photon energy ARPES have been observed for both materials by virtue of the high $3d$ sensitivity as well as high bulk sensitivity. Coexistence of a quasiparticle peak with an incoherent peak is observed in the metallic phase of ${\mathrm{V}}_6{\mathrm{O}}_{13}$, whereas the quasiparticle peak collapses in the insulator phase, in which two incoherent peaks are observed. In $\mathrm{Sr}\mathrm{Cu}{\mathrm{O}}_2$, the dispersive behavior of the spectra is well understood on the basis of the one-dimensional half-filled Hubbard model with $U∕t=7.5$ and $U=3.0\mathrm{eV}$ ($U$: Coulomb repulsive energy and $t$: transfer energy) and substantial coupling between the spin and charge excitations is suggested.