Plasmon assisted superconductivity in LiTi${}_2$O${}_4$

Abstract

We combine $GW$ plus extended dynamical mean field theory ($GW$+EDMFT) with the density functional theory for superconductors (SCDFT) framework to study the electronic properties of LiTi${}_2$O${}_4$. Excellent agreement with experiment is obtained for the density of states, mass enhancement, Sommerfeld coefficient and superconducting $T_c$, if the dynamical nature of the screened Coulomb interaction is taken into account. Our results show that the coupling to collective charge fluctuations (plasmons) plays an important role in the pairing mechanism and explains the remarkably high $T_c$ of this moderately correlated spinel compound.