Ab-initio Phonon Calculations for the layered compound TiOCl

TL;DR

This paper uses first-principles calculations to analyze phonon modes in TiOCl, showing that including electron correlation via LDA+U improves agreement with experiments and impacts the understanding of its physics.

Contribution

It compares LDA and LDA+U approaches for phonon calculations in TiOCl, highlighting the importance of electron correlation for accurate results.

Findings

LDA+U yields better agreement with experimental phonon frequencies.

Electron correlation significantly influences the phonon properties of TiOCl.

The study discusses the physical implications of different computational approaches.

Abstract

We present first-principles frozen-phonon calculations for the three Raman-active $A_g$ modes in the spin-1/2 layered TiOCl system within two different well-known approaches: the local density approximation (LDA) and the so-called LDA+U approximation. We observe that the inclusion of electron correlation in a mean-field level as implemented in the LDA+U leads to a better overall agreement with experimental results. We also discuss the implications of the two approaches on the physics of TiOCl.