One-dimensional versus two-dimensional correlation effects in the oxyhalides TiOCl and TiOBr

TL;DR

This study compares the electronic structures of TiOCl and TiOBr, revealing that bromide is less one-dimensional and emphasizing the importance of anisotropic interchain interactions for understanding their normal state electronic properties.

Contribution

It provides a detailed comparative analysis of TiOCl and TiOBr's electronic structures, highlighting the role of anisotropic frustrated interchain interactions.

Findings

TiOBr is less one-dimensional than TiOCl.

Normal state electronic structure requires considering anisotropic frustrated interchain interactions.

Both compounds exhibit similar overall electronic structures despite differences.

Abstract

We have performed a comparative study of the electronic structures of the spin-Peierls systems TiOCl and TiOBr by means of photoemission spectroscopy and density functional calculations. While the overall electronic structure of these isostructural compounds is qualitatively similar, the bromide appears to be less one-dimensional. We present a quantitative analysis of the experimental dispersions in terms of exchange constant J and hopping integral t as well as a discussion of the qualitative spectral features. From that we conclude that despite the one-dimensional physics triggering the ground state in both compounds a proper description of the normal state electronic structure has to take into account the anisotropic frustrated interchain interactions on the underlying triangular lattice.