We present an ab initio $GW$ calculation to study dynamical effects on an organic compound (TMTSF)${}_2$PF${}_6$. Calculated polarized reflectivities reproduce experimental plasma edges at around 0.2 eV for $E\parallel b^{\prime }$ and 1.0 eV for $E\parallel a$. The low-energy plasmons come out from the low-energy narrow bands energetically isolated from other higher-energy bands, and affect the low-energy electronic structure via the $GW$-type self-energy. Because of the quasi-one-dimensional band structure, a distinct plasmaron state is observed along the $Y$-$\Gamma$ line and a large plasmon-induced electron scattering is found in the low-energy occupied states along the $X$-$M$ line.

• Received 10 April 2013

DOI:https://doi.org/10.1103/PhysRevB.88.125128