Enhanced strange metallicity due to Coulomb repulsion

We solve a model of electrons with Hubbard-$U$ Coulomb repulsion and a random

Yukawa coupling to a two-dimensional bosonic bath, using an extended dynamical

mean field theory scheme. Our model exhibits a quantum critical point, at which

the repulsive component of the electron interactions strongly enhances the

effects of the quantum critical bosonic fluctuations on the electrons, leading

to a breakdown of Fermi liquid physics and the formation of a strange metal

with `Planckian' ($\mathcal{O}(k_B T/\hbar)$) quasiparticle decay rates at low

temperatures $T\rightarrow 0$. Furthermore, the eventual Mott transition that

occurs as the repulsion is increased seemingly bounds the maximum decay rate in

the strange metal. Our results provide insight into low-temperature

strange metallicity observed in proximity to a Mott transition, as is observed,

for instance, in recent experiments on certain moir\'{e} materials.