Pressure-Induced Confined Metal from the Mott Insulator Sr3Ir2O7

TL;DR

This study reveals a pressure-induced insulator-metal transition in Sr3Ir2O7, where the material becomes metallic in-plane but remains insulating out-of-plane, driven likely by structural changes rather than electronic interactions.

Contribution

It demonstrates a novel pressure-driven insulator-metal transition with anisotropic metallicity in Sr3Ir2O7, highlighting a new pathway for functional material synthesis.

Findings

Material becomes metallic in the ab plane at 59.5 GPa

Insulating behavior persists along the c axis under high pressure

Transition likely driven by structural change, not electronic collapse

Abstract

The spin-orbit Mott insulator Sr3Ir2O7 provides a fascinating playground to explore insulator-metal transition driven by intertwined charge, spin, and lattice degrees of freedom. Here, we report high pressure electric resistance and resonant inelastic x ray scattering measurements on single crystal Sr3Ir2O7 up to 63 65 GPa at 300 K. The material becomes a confined metal at 59.5 GPa, showing metallicity in the ab plane but an insulating behavior along the c axis. Such an unusual phenomenon resembles the strange metal phase in cuprate superconductors. Since there is no sign of the collapse of spin orbit or Coulomb interactions in x-ray measurements, this novel insulator metal transition is potentially driven by a first-order structural change at nearby pressures. Our discovery points to a new approach for synthesizing functional materials.