Charge Density Wave and Superconductivity in the Disordered Holstein Model

The interplay between electron-electron correlations and disorder has
been a central theme of condensed matter physics over the last several
decades, with the possibility that interactions might cause
delocalization of an Anderson insulator into a metallic state, and the
disrupting effects of randomness on magnetic order and the Mott phase
both being central themes of investigation. Here we extend this
physics to explore electron-phonon interactions and
show, via exact quantum Monte Carlo simulations, that the suppression
of the charge density wave correlations in the half-filled Holstein
model by disorder can stabilize a superconducting phase.
We discuss the relationship of our work to studies of the
disorder quenching of the charge ordered phase in ZrTe₃ through Se doping, and the
interplay with the observed superconductivity in that material,
reproducing the qualitative features of the phase diagram in the
temperature-disorder strength plane.