Pressure-tuned spin chains in brochantite, Cu$_4$SO$_4$(OH)$_6$

Fuente: arXiv
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Main Authors: Ginga, Victoria A., Shen, Bin, Uykur, Ece, Giordano, Nico, Gegenwart, Philipp, Tsirlin, Alexander A.
Format: Preprint
Published: 2025
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author Ginga, Victoria A.
Shen, Bin
Uykur, Ece
Giordano, Nico
Gegenwart, Philipp
Tsirlin, Alexander A.
author_facet Ginga, Victoria A.
Shen, Bin
Uykur, Ece
Giordano, Nico
Gegenwart, Philipp
Tsirlin, Alexander A.
contents Using high-pressure single-crystal x-ray diffraction combined with thermodynamic measurements and density-functional calculations, we uncover the microscopic magnetic model of the mineral brochantite, Cu$_4$SO$_4$(OH)$_6$, and its evolution upon compression. The formation of antiferromagnetic spin chains with the effective intrachain coupling of $J\simeq 100$\,K is attributed to the occurrence of longer Cu--Cu distances and larger Cu--O--Cu bond angles between the structural chains within the layers of the brochantite structure. These zigzag spin chains are additionally stabilized by ferromagnetic couplings $J_2$ between second neighbors and moderately frustrated by several antiferromagnetic couplings that manifest themselves in the reduced Néel temperature of the material. Pressure tuning of the brochantite structure keeps its monoclinic symmetry unchanged and leads to the growth of antiferromagnetic $J$ with the rate of 3.2\,K/GPa, although this trend is primarily caused by the enhanced ferromagnetic couplings $J_2$. Our results show that the nature of magnetic couplings in brochantite and in other layered Cu$^{2+}$ minerals is controlled by the size of the lattice translation along their structural chains and by the extent of the layer buckling.
format Preprint
id arxiv_https___arxiv_org_abs_2504_12057
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Pressure-tuned spin chains in brochantite, Cu$_4$SO$_4$(OH)$_6$
Ginga, Victoria A.
Shen, Bin
Uykur, Ece
Giordano, Nico
Gegenwart, Philipp
Tsirlin, Alexander A.
Strongly Correlated Electrons
Other Condensed Matter
Using high-pressure single-crystal x-ray diffraction combined with thermodynamic measurements and density-functional calculations, we uncover the microscopic magnetic model of the mineral brochantite, Cu$_4$SO$_4$(OH)$_6$, and its evolution upon compression. The formation of antiferromagnetic spin chains with the effective intrachain coupling of $J\simeq 100$\,K is attributed to the occurrence of longer Cu--Cu distances and larger Cu--O--Cu bond angles between the structural chains within the layers of the brochantite structure. These zigzag spin chains are additionally stabilized by ferromagnetic couplings $J_2$ between second neighbors and moderately frustrated by several antiferromagnetic couplings that manifest themselves in the reduced Néel temperature of the material. Pressure tuning of the brochantite structure keeps its monoclinic symmetry unchanged and leads to the growth of antiferromagnetic $J$ with the rate of 3.2\,K/GPa, although this trend is primarily caused by the enhanced ferromagnetic couplings $J_2$. Our results show that the nature of magnetic couplings in brochantite and in other layered Cu$^{2+}$ minerals is controlled by the size of the lattice translation along their structural chains and by the extent of the layer buckling.
title Pressure-tuned spin chains in brochantite, Cu$_4$SO$_4$(OH)$_6$
topic Strongly Correlated Electrons
Other Condensed Matter
url https://arxiv.org/abs/2504.12057