Theory of stripes in quasi two dimensional rare-earth tritellurides

TL;DR

This paper develops a theoretical understanding of stripe and checkerboard charge density wave phases in quasi-2D rare-earth tritellurides, explaining experimental observations and providing insights into similar phenomena in correlated materials.

Contribution

It introduces a theoretical framework predicting when stripe versus checkerboard CDW order occurs based on transition temperature, linking band structure to charge order patterns.

Findings

Stripe order is favored at higher transition temperatures.

Checkerboard order occurs at lower transition temperatures.

The theory explains observed charge order patterns in experiments.

Abstract

Even though the rare-earth tritellurides are tetragonal materials with a quasi two dimensional (2D) band structure, they have a "hidden" 1D character. The resultant near-perfect nesting of the Fermi surface leads to the formation of a charge density wave (CDW) state. We show that for this band structure, there are two possible ordered phases: A bidirectional "checkerboard" state would occur if the CDW transition temperature were sufficiently low, whereas a unidirectional "striped" state, consistent with what is observed in experiment, is favored when the transition temperature is higher. This result may also give some insight into why, in more strongly correlated systems, such as the cuprates and nickelates, the observed charge ordered states are generally stripes as opposed to checkerboards.