Spatial localization of magnetic-branch force contrasts in substitutional Mn-doped Ge: A first-principles study
Abstract
Magnetic energy gaps do not reveal the spatial distribution of magnetic-state-dependent atomic forces. We compare ferromagnetic and antiferromagnetic forces at identical nuclear positions in 64-site substitutional Mn-doped Ge using collinear PBE calculations. For nearest-neighbour Mn pairs, the radial force projection reverses sign between magnetic branches. In the second-neighbour geometry, the shared Ge neighbour has the largest force contrast, about 2.2 times that of equally near Ge sites coordinated to one Mn. Bridge-displacement gap slopes agree with direct force derivatives across four numerical settings. Tightening the electronic threshold by 100-fold preserves magnetic ordering and the leading site, while the force-contrast vector changes by 1.08% despite a nearly unchanged energy gap. The results identify coordination-associated localization of magnetic-branch force contrasts within the frozen model, without establishing relaxed distortions, full numerical convergence or a unique exchange mechanism.
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BibTeX
@misc{chen2026spatial,
title = {{Spatial localization of magnetic-branch force contrasts in substitutional Mn-doped Ge: A first-principles study}},
author = {ChienHsu Chen},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.36740},
eprint = {2610.36740},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.36740},
}
RIS
TY - UNPB
TI - Spatial localization of magnetic-branch force contrasts in substitutional Mn-doped Ge: A first-principles study
AU - ChienHsu Chen
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2610.36740
UR - https://arxiv.org/abs/2610.36740
AB - Magnetic energy gaps do not reveal the spatial distribution of magnetic-state-dependent atomic forces. We compare ferromagnetic and antiferromagnetic forces at identical nuclear positions in 64-site substitutional Mn-doped Ge using collinear PBE calculations. For nearest-neighbour Mn pairs, the radial force projection reverses sign between magnetic branches. In the second-neighbour geometry, the shared Ge neighbour has the largest force contrast, about 2.2 times that of equally near Ge sites coordinated to one Mn. Bridge-displacement gap slopes agree with direct force derivatives across four numerical settings. Tightening the electronic threshold by 100-fold preserves magnetic ordering and the leading site, while the force-contrast vector changes by 1.08% despite a nearly unchanged energy gap. The results identify coordination-associated localization of magnetic-branch force contrasts within the frozen model, without establishing relaxed distortions, full numerical convergence or a unique exchange mechanism.
ER -