Gd-4f Exchange Splitting and Mo-4d Crystal-Field Redistribution in Gd/W Co-doped La2Mo2O9: A DFT+U Study
Abstract
La2Mo2O9 (LAMOX) is a promising oxide-ion conductor for intermediate-temperature solid oxide fuel cells, but its practical application is limited by a first-order monoclinic-to-cubic (alpha to beta) phase transition. Here, we investigate the electronic structure of pristine La2Mo2O9 and the Gd/W co-doped composition La1.6Gd0.4Mo1.7W0.3O9 using spin-polarized density functional theory with an on-site Hubbard correction for the localized Gd-4f states. The projected density of states reveals that pristine La2Mo2O9 is an O-2p/Mo-4d charge-transfer oxide in which La contributes negligibly near the band edges. Gd/W co-doping introduces a strongly exchange-split Gd-4f manifold with a majority-minority separation of approximately 1011 eV, substantially redistributes the Mo-4d electronic states through a threefold increase in crystal-field splitting, and reduces the O-2p contribution near the valence-band maximum from 78% to 66%. These electronic signatures are consistent with the experimentally observed lattice contraction, MoO Raman-mode softening, and the non-monotonic evolution of oxide-ion conductivity across the co-doped series. In particular, the pronounced crystal-field splitting and localized Gd magnetism at the highest doping level provide a microscopic electronic explanation for the observed suppression of ionic conductivity. The present results establish an atomistic electronic-structure framework for understanding dopant-induced phase stabilization and oxide- ion transport in Gd/W co-doped LAMOX electrolytes, providing design principles for improved solid oxide fuel cell materials.
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BibTeX
@misc{lanjewar2026gd4f,
title = {{Gd-4f Exchange Splitting and Mo-4d Crystal-Field Redistribution in Gd/W Co-doped La2Mo2O9: A DFT+U Study}},
author = {Amogh U. Lanjewar and Saurabh Shiwankar and Smita Acharya},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.03717},
eprint = {2609.03717},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.03717},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Gd-4f Exchange Splitting and Mo-4d Crystal-Field Redistribution in Gd/W Co-doped La2Mo2O9: A DFT+U Study
AU - Amogh U. Lanjewar
AU - Saurabh Shiwankar
AU - Smita Acharya
PY - 2026
DA - 2026/09/03
PB - arXiv
DO - 10.48550/arxiv.2609.03717
UR - https://arxiv.org/abs/2609.03717
AB - La2Mo2O9 (LAMOX) is a promising oxide-ion conductor for intermediate-temperature solid oxide fuel cells, but its practical application is limited by a first-order monoclinic-to-cubic (alpha to beta) phase transition. Here, we investigate the electronic structure of pristine La2Mo2O9 and the Gd/W co-doped composition La1.6Gd0.4Mo1.7W0.3O9 using spin-polarized density functional theory with an on-site Hubbard correction for the localized Gd-4f states. The projected density of states reveals that pristine La2Mo2O9 is an O-2p/Mo-4d charge-transfer oxide in which La contributes negligibly near the band edges. Gd/W co-doping introduces a strongly exchange-split Gd-4f manifold with a majority-minority separation of approximately 1011 eV, substantially redistributes the Mo-4d electronic states through a threefold increase in crystal-field splitting, and reduces the O-2p contribution near the valence-band maximum from 78% to 66%. These electronic signatures are consistent with the experimentally observed lattice contraction, MoO Raman-mode softening, and the non-monotonic evolution of oxide-ion conductivity across the co-doped series. In particular, the pronounced crystal-field splitting and localized Gd magnetism at the highest doping level provide a microscopic electronic explanation for the observed suppression of ionic conductivity. The present results establish an atomistic electronic-structure framework for understanding dopant-induced phase stabilization and oxide- ion transport in Gd/W co-doped LAMOX electrolytes, providing design principles for improved solid oxide fuel cell materials.
ER -