Spin liquid properties of the kagome material Cu$_3$(HOTP)$_2$

Fuente: arXiv
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Auteurs principaux: Pratt, F. L., Lopez-Alcala, D., Garcia-Lopez, V., Clemente-Leon, M., Baldovi, J. J., Coronado, E.
Format: Preprint
Publié: 2024
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author Pratt, F. L.
Lopez-Alcala, D.
Garcia-Lopez, V.
Clemente-Leon, M.
Baldovi, J. J.
Coronado, E.
author_facet Pratt, F. L.
Lopez-Alcala, D.
Garcia-Lopez, V.
Clemente-Leon, M.
Baldovi, J. J.
Coronado, E.
contents The metal-organic-framework (MOF) compound Cu$_3$(HOTP)$_2$, a.k.a. Cu$_3$(HHTP)$_2$, is a small-gap semiconductor containing a kagome lattice of antiferromagnetically coupled $S$=1/2 Cu$^\mathrm{II}$ spins with intra-layer nearest-neighbor exchange coupling $J \sim $ 2 K. The intra-layer $J$ value obtained from DFT+U calculations is shown to match with the experimental value for reasonable values of U. Muon spin relaxation confirms no magnetic ordering down to 50~mK and sees spin fluctuations diffusing on a 2D lattice, consistent with a quantum spin liquid (QSL) ground state being present within highly decoupled kagome layers. Reduction of the spin diffusion rate on cooling from the paramagnetic region to the low-temperature QSL region reflects quantum entanglement. It is also found that the layers become more strongly decoupled in the low-temperature QSL region. Comparison of results for the spin diffusion, magnetic susceptibility and specific heat in the QSL region suggests close proximity to a quantum critical point and a large density of low energy spinless electronic excitations. A Z$_2$-linear Dirac model for the spin excitations of the QSL is found to provide the best match with experiment.
format Preprint
id arxiv_https___arxiv_org_abs_2411_18518
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Spin liquid properties of the kagome material Cu$_3$(HOTP)$_2$
Pratt, F. L.
Lopez-Alcala, D.
Garcia-Lopez, V.
Clemente-Leon, M.
Baldovi, J. J.
Coronado, E.
Strongly Correlated Electrons
The metal-organic-framework (MOF) compound Cu$_3$(HOTP)$_2$, a.k.a. Cu$_3$(HHTP)$_2$, is a small-gap semiconductor containing a kagome lattice of antiferromagnetically coupled $S$=1/2 Cu$^\mathrm{II}$ spins with intra-layer nearest-neighbor exchange coupling $J \sim $ 2 K. The intra-layer $J$ value obtained from DFT+U calculations is shown to match with the experimental value for reasonable values of U. Muon spin relaxation confirms no magnetic ordering down to 50~mK and sees spin fluctuations diffusing on a 2D lattice, consistent with a quantum spin liquid (QSL) ground state being present within highly decoupled kagome layers. Reduction of the spin diffusion rate on cooling from the paramagnetic region to the low-temperature QSL region reflects quantum entanglement. It is also found that the layers become more strongly decoupled in the low-temperature QSL region. Comparison of results for the spin diffusion, magnetic susceptibility and specific heat in the QSL region suggests close proximity to a quantum critical point and a large density of low energy spinless electronic excitations. A Z$_2$-linear Dirac model for the spin excitations of the QSL is found to provide the best match with experiment.
title Spin liquid properties of the kagome material Cu$_3$(HOTP)$_2$
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2411.18518