Insulating Ferromagnetism in La$_{4}$Ba$_{2}$Cu$_{2}$O$_{10}$: an \textit{Ab Initio} Wannier Function Analysis

Wei Ku; H. Rosner; W. E. Pickett; R. T. Scalettar

doi:10.1103/PhysRevLett.89.167204

paper

Insulating Ferromagnetism in La $_{4}$ Ba $_{2}$ Cu $_{2}$ O $_{10}$ : an \textit{Ab Initio} Wannier Function Analysis

arXiv:cond-mat/0205300 · doi:10.1103/PhysRevLett.89.167204

Abstract

Microscopic mechanisms of the puzzling insulating ferromagnetism of half-filled La $_{4}$ Ba $_{2}$ Cu $_{2}$ O $_{10}$ are elucidated with energy-resolved Wannier states. The dominant magnetic coupling, revealed through evaluated parameters ( $t$ , $U$ , and $J$ ), turns out to be the intersite direct exchange, a currently ignored mechanism that overwhelms the antiferromagnetic superexchange. By contrast, the isostructural Nd $_{4}$ Ba $_{2}$ Cu $_{2}$ O $_{10}$ develops the observed antiferromagnetic order via its characteristics of a 1D chain. Surprisingly, the in-plane order of both cases is \textit{not} controlled by coupling between nearest neighbors. An intriguing pressure-induced ferromagnetic to antiferromagnetic transition is predicted.

4 pages, 3 color figures

Insulating Ferromagnetism in La4​Ba2​Cu2​O10​: an \textit{Ab Initio} Wannier Function Analysis

Abstract

Insulating Ferromagnetism in La $_{4}$ Ba $_{2}$ Cu $_{2}$ O $_{10}$ : an \textit{Ab Initio} Wannier Function Analysis