Bloch electrons in a Jahn-Teller crystal and an orbital-density-wave state due to the Berry phase

TL;DR

This paper investigates how the Berry phase influences the electronic band structure in Jahn-Teller crystals, leading to orbital-density-wave states and potentially explaining orbital ordering phenomena in manganese perovskites.

Contribution

It explicitly incorporates the Berry phase into the conduction electron wavefunction in Jahn-Teller crystals, revealing its role in band structure modifications and orbital ordering.

Findings

Berry phase causes significant band structure changes

Orbital-density-wave state formation due to Berry phase effects

Potential explanation for orbital ordering in manganese perovskites

Abstract

The effect of the Berry phase is included explicitly in the wavefunction describing conduction electrons in a crystal composed of periodically arrayed Jahn-Teller centers that have conically intersecting potential energy surfaces. The Berry phase can make a drastic change in the band structure, leading generally to the formation of an orbital-density-wave state. We discuss implications of our theory and possible relations to the orbital ordering observed in the manganese perovskites.