dorsal/arxiv
View SchemaQuasiparticle to local moment crossover in bad metals
| Authors | A. Chen, F. B. Kugler, P. Doležal, Y. Saito, A. Kawamoto, A. Georges, A. Pustogow |
|---|---|
| Categories | |
| ArXiv ID | 2601.09420vv1 |
| URL | https://arxiv.org/abs/2601.09420 |
| License | http://creativecommons.org/licenses/by-nc-nd/4.0/ |
Abstract
Non-Fermi-liquid charge transport in the vicinity of electronic instabilities has been intensely studied for decades. Deviations from $\rho_{\rm FL}=\rho_0+AT^2$ in bad and strange metals are commonly ascribed to a breakdown of Landau's quasiparticle (QP) concept. Yet, it remains unclear what mechanism drives the temperature dependence of $\rho(T)$ beyond $\rho_{\rm FL}$. Here, we examine the bad metal upon approaching the Mott metal-insulator transition via chemical pressure in $\kappa$-[(BEDT-STF)$_x$(BEDT-TTF)$_{1-x}$]$\rm _2 Cu_2 (CN)_3$. Through nuclear magnetic resonance (NMR) and transport experiments on the same single crystals, we directly link the onset of deviations from Korringa law $(T_1T)^{-1} = \mathrm{const.}$ with the rise of $\rho(T)$ beyond $\rho_{\rm FL}$. From the NMR relaxation rate, we can identify the gradual crossover between the QP-dominated regime at low $T$ to predominant local moments at higher $T$. By comparing our experimental findings with dynamical mean-field theory calculations, which accurately reproduce the transport data, we reveal how this crossover is reflected in $T$-dependent changes of the QP spectrum. Near the Mott insulator, where $d\rho/dT<0$ at high $T$, an Einstein-relation analysis shows that bad-metal behavior with $d\rho/dT>0$ is driven by the temperature dependence of the electronic compressibility rather than the diffusion constant.
{
"annotation_id": "eb9dcf54-f261-4c7d-a230-33949ed15bca",
"date_created": "2026-02-17T05:53:19.911000Z",
"date_modified": "2026-02-17T05:53:19.911000Z",
"file_hash": "31affe47d028ae50a3e9abf365981e84b5d7d83f6722028d5c9600406cbea705",
"private": false,
"record": {
"abstract": "Non-Fermi-liquid charge transport in the vicinity of electronic instabilities has been intensely studied for decades. Deviations from $\\rho_{\\rm FL}=\\rho_0+AT^2$ in bad and strange metals are commonly ascribed to a breakdown of Landau\u0027s quasiparticle (QP) concept. Yet, it remains unclear what mechanism drives the temperature dependence of $\\rho(T)$ beyond $\\rho_{\\rm FL}$. Here, we examine the bad metal upon approaching the Mott metal-insulator transition via chemical pressure in $\\kappa$-[(BEDT-STF)$_x$(BEDT-TTF)$_{1-x}$]$\\rm _2 Cu_2 (CN)_3$. Through nuclear magnetic resonance (NMR) and transport experiments on the same single crystals, we directly link the onset of deviations from Korringa law $(T_1T)^{-1} = \\mathrm{const.}$ with the rise of $\\rho(T)$ beyond $\\rho_{\\rm FL}$. From the NMR relaxation rate, we can identify the gradual crossover between the QP-dominated regime at low $T$ to predominant local moments at higher $T$. By comparing our experimental findings with dynamical mean-field theory calculations, which accurately reproduce the transport data, we reveal how this crossover is reflected in $T$-dependent changes of the QP spectrum. Near the Mott insulator, where $d\\rho/dT\u003c0$ at high $T$, an Einstein-relation analysis shows that bad-metal behavior with $d\\rho/dT\u003e0$ is driven by the temperature dependence of the electronic compressibility rather than the diffusion constant.",
"arxiv_id": "2601.09420",
"authors": [
"A. Chen",
"F. B. Kugler",
"P. Dole\u017eal",
"Y. Saito",
"A. Kawamoto",
"A. Georges",
"A. Pustogow"
],
"categories": [
"cond-mat.str-el"
],
"license": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
"title": "Quasiparticle to local moment crossover in bad metals",
"url": "https://arxiv.org/abs/2601.09420",
"version": "v1"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "1434311e-7699-4ad7-95bc-9c09397decdf",
"id": "arXiv Dataset",
"type": "Model",
"variant": "snapshot-2026-01-17",
"version": "0.1.0"
},
"user_id": 1000002
}