Density functionals and half-metalicity in La2/3Sr1/3MnO3

TL;DR

This paper investigates the electronic structure and geometry of La2/3Sr1/3MnO3 using density functional theory, highlighting differences between LDA and GGA approximations and their implications for half-metallicity.

Contribution

It provides a comparative analysis of LDA and GGA functionals in modeling La2/3Sr1/3MnO3, demonstrating GGA's improved accuracy and its ability to predict half-metallic behavior.

Findings

GGA yields a more realistic volume than LDA.

GGA predicts half-metallicity in the relaxed structure.

LDA results agree with previous calculations but underestimate volume.

Abstract

The electronic structure and equilibrium geometry of La2/3Sr1/3MnO3 are studied theoretically by means of density functional calculations. The doping is treated by introducing holes and a compensating jellium background. The results for the local density approximation (LDA) agree with previous LDA calculations, with an equilibrium volume 5.3% too small and with both majority and minority spin states present at the Fermi level for the relaxed system. The generalised gradient approximation (GGA) offers a qualitatively improved description of the system, with a more realistic volume, and a half-metallic behaviour for the relaxed structure, which enables studies needing theoretical relaxation.The ideal MnO2-terminated (001) surface is then described with explicit doping.