Surface magnetism of Rh(001) from LDA+U calculations

TL;DR

This study uses LDA+U calculations to demonstrate surface magnetism in Rh(001), reconciling experimental observations with theoretical predictions by incorporating on-site Coulomb interactions.

Contribution

It introduces the application of GGA+U to predict surface magnetism in Rh(001), resolving previous discrepancies between theory and experiment.

Findings

GGA+U predicts surface magnetic moments where LDA/GGA do not.

Surface magnetic moment increases with Ueff, reaching 1.24 μ_B at Ueff=2.5 eV.

The results align theoretical predictions with experimental evidence.

Abstract

We report calculations indicating the presence of a surface magnetic moment for Rh(001), motivated by the detection of a finite moment by magnetic linear dichroism experiments. We show that, while the density functional with the local density or generalized gradient approximations (LDA and GGA) for exchange and correlation yields a non-magnetic ground state, the application of the GGA plus on-site Coulomb interaction U method predicts surface magnetism, thus offering a solution to the long-standing discrepancy between experiment and theory. The calculated moment on the outermost Rh atom increases with the strength of the effective on-site parameter Ueff=U-J, for Ueff>=1.2 eV, and is as large as 1.24 mu_B for Ueff=2.5 eV.