Hidden Phases Revealed at the Surface of Double-Layered Sr3(Ru1-xMnx)2O7

TL;DR

This study reveals that surface modifications in Sr3(Ru1-xMnx)2O7 can uncover hidden electronic and structural phases different from the bulk, highlighting the surface as a tool for exploring complex material behaviors.

Contribution

It demonstrates that surface properties can reveal hidden phases in layered oxides, differing from bulk behavior, through structural and electronic analysis.

Findings

Surface of Sr3Ru2O7 is less metallic than bulk due to tilt distortion.

Mn-doping induces metallic surface while bulk remains insulating.

Surface and bulk properties are coupled and exhibit quasi two-dimensionality.

Abstract

Double-layered Sr3Ru2O7 has received phenomenal consideration because it exhibits a plethora of exotic phases when perturbed. New phases emerge with the application of pressure, magnetic field, or doping. Here we show that creating a surface is an alternative and effective way to reveal hidden phases that are different from those seen in the bulk by investigating the surface properties of Sr3(Ru1-xMnx)2O7. Driven by the tilt distortion of RuO6 octahedra, the surface of Sr3Ru2O7 is less metallic than the bulk. In contrast, because of the vanishing of tilt and enhanced rotation with Mn-doping, the surface of Sr3(Ru0.84Mn0.16)2O7 is metallic while the bulk is insulating. Our result demonstrates that the electronic and structural properties at the surface are intimately coupled and consistent with quasi two-dimensional character.