Observation and Structural Control of Charge-Density-Waves resonating with Terahertz Frequencies in NdNiO3

TL;DR

This study provides the first evidence of charge-density-waves in NdNiO3 using terahertz spectroscopy, revealing their structure-dependent dynamics and potential for oxide electronic applications.

Contribution

It demonstrates the direct observation of charge-density-waves in NdNiO3 and links their behavior to crystal symmetry and structure-property relationships.

Findings

Charge-density-waves observed at 5meV in NdNiO3.

Distinct charge dynamics linked to orthorhombic and cubic symmetries.

Charge-density-waves can be controlled via structural symmetry.

Abstract

Formation of charge-density-waves in ordered electronic phases (such as charge-order) is an emergent phenomenon in the perovskite class of correlated oxides. This scenario is visualized to prevail in exotic RNiO3 (R=rare-earth) nickelates in which the structure controls the incipient charge-order to form in weak localization limit. However, any consequent effect demonstrating these nickelates in rare category of charge-density-waves conductors with controlled charge-lattice interactions has been a fundamental challenge so-far. Here, we present first evidence of the charge-density-waves in a prototypical NdNiO3 system employing terahertz time-domain spectroscopy along selective crystal axes. A finite peak structure at 5meV in the terahertz conductivity displays all the characteristics of a charge-density-wave condensate. Contrasting charge-dynamics of collective charge-density-waves mode and Drude conductivity emerging, respectively, from orthorhombic and cubic symmetries disentangle charge-ordering from the insulating state, establish a novel structure-property cause-effect relationship, and present opportunities to harness these diverse attributes in oxide electronics.