Emergent charge order near the doping-induced Mott-insulating quantum phase transition in Sr$_{3}$Ru$_{2}$O$_{7}$

TL;DR

This study reveals how doping induces a Mott-insulating state and emergent charge order in Sr$_{3}$Ru$_{2}$O$_{7}$, highlighting universal features of doped Mott insulators through spectroscopic imaging.

Contribution

First direct visualization of charge order emergence near a doping-induced Mott transition in Sr$_{3}$Ru$_{2}$O$_{7}$ using STM.

Findings

Partial gap develops with doping indicating Mott insulating state.

Spatial charge order forms near the quantum phase transition.

Charge order resembles that in cuprate pseudogap phases.

Abstract

We investigate the double layered Sr$_{3}$(Ru$_{1-x}$Mn$_{x}$)$_{2}$O$_{7}$ and its doping-induced quantum phase transition (QPT) from a metal to an antiferromagnetic (AFM) Mott insulator. Using spectroscopic imaging with the scanning tunneling microscope (STM), we visualize the evolution of the electronic states in real- and momentum-space. We find a partial-gap in the tunneling density of states at the Fermi energy (E$_{F}$) that develops with doping to form a weak Mott insulating ({\Delta} ~ 100meV) state. Near the QPT, we discover a spatial electronic reorganization into a commensurate checkerboard charge order. These findings share some resemblance to the well-established universal charge order in the pseudogap phase of cuprates. Our experiments therefore demonstrate the ubiquity of the incipient charge order that emanates from doped Mott insulators.