Spectral properties of quasi-one-dimensional insulator: Influence of dipolar excitation

This work is extension of previous considerations of the spectral properties of quasi-one-dimensional bands using G0W0 approximation with the three-dimensional long-range Coulomb electron-electron interaction for the investigation of the spectral properties of valence band electrons in the quasi-one-dimensional band insulator for which one has to take into account interband excitations. Within the random phase approximation (RPA) quasi-one-dimensional band insulator with two electron bands has a interband dipolar mode. Derived spectral function comprises broad dispersing structure due to this mode. Obtained spectral properties are brought in correspondence with ARPES data of red bronze K0.33MoO3.