Fermi-liquid versus non-Fermi-liquid/'strange-metal' fits to the electrical resistivity in the quantum critical magnetic regime of an unconventional superconductor
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2026
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| author | Knafo, W. Thebault, T. Somesh, K. Lapertot, G. Knebel, G. Braithwaite, D. Aoki, D. |
| author_facet | Knafo, W. Thebault, T. Somesh, K. Lapertot, G. Knebel, G. Braithwaite, D. Aoki, D. |
| contents | The question of a possible quantum critical point lying inside of a superconducting phase is central for understanding unconventional superconductivity. In various unconventional superconductors, non-Fermi-liquid/'strange-metal' $T^{n}$ variations, with $n<2$, of the electrical resistivity have been identified as the signature of magnetic quantum criticality. However, a difficulty is to prove experimentally that a non-Fermi-liquid/'strange-metal' law identified at temperatures above the superconducting temperature is the signature of an intrinsic zero-temperature quantum critical regime. In the heavy-fermion paramagnet UTe$_2$, unconventional superconductivity develops in the vicinity of a metamagnetic quantum phase transition induced by a magnetic field, and the quantum critical magnetic properties are suspected to play a role for the superconducting mechanism. In this work, we present a comparative analysis of electrical resistivity data collected on two UTe$_2$ samples of different qualities, in magnetic fields tilted by angles $θ\simeq35-40$~$^\circ$ from $\mathbf{b}$ to $\mathbf{c}$. Fits to the data have been performed either with a Fermi-liquid function $ρ=ρ_0+AT^{2}$ or with a non-Fermi-liquid/'strange-metal' function $ρ=ρ_0+A_nT^n$. Near to a superconducting phase induced beyond 40~T, non-physical residual resistivities $ρ_0<0$ are extracted from the $T^n$ fits, revealing that a 'hidden' Fermi-liquid $T^2$ regime may be ultimately recovered at low temperature. The results obtained here highlight the importance to investigate high-quality samples with low residual resistivity to confirm - or not - the presence of a suspected 'hidden' quantum critical behavior masked by superconductivity. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2604_14952 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Fermi-liquid versus non-Fermi-liquid/'strange-metal' fits to the electrical resistivity in the quantum critical magnetic regime of an unconventional superconductor Knafo, W. Thebault, T. Somesh, K. Lapertot, G. Knebel, G. Braithwaite, D. Aoki, D. Superconductivity Strongly Correlated Electrons The question of a possible quantum critical point lying inside of a superconducting phase is central for understanding unconventional superconductivity. In various unconventional superconductors, non-Fermi-liquid/'strange-metal' $T^{n}$ variations, with $n<2$, of the electrical resistivity have been identified as the signature of magnetic quantum criticality. However, a difficulty is to prove experimentally that a non-Fermi-liquid/'strange-metal' law identified at temperatures above the superconducting temperature is the signature of an intrinsic zero-temperature quantum critical regime. In the heavy-fermion paramagnet UTe$_2$, unconventional superconductivity develops in the vicinity of a metamagnetic quantum phase transition induced by a magnetic field, and the quantum critical magnetic properties are suspected to play a role for the superconducting mechanism. In this work, we present a comparative analysis of electrical resistivity data collected on two UTe$_2$ samples of different qualities, in magnetic fields tilted by angles $θ\simeq35-40$~$^\circ$ from $\mathbf{b}$ to $\mathbf{c}$. Fits to the data have been performed either with a Fermi-liquid function $ρ=ρ_0+AT^{2}$ or with a non-Fermi-liquid/'strange-metal' function $ρ=ρ_0+A_nT^n$. Near to a superconducting phase induced beyond 40~T, non-physical residual resistivities $ρ_0<0$ are extracted from the $T^n$ fits, revealing that a 'hidden' Fermi-liquid $T^2$ regime may be ultimately recovered at low temperature. The results obtained here highlight the importance to investigate high-quality samples with low residual resistivity to confirm - or not - the presence of a suspected 'hidden' quantum critical behavior masked by superconductivity. |
| title | Fermi-liquid versus non-Fermi-liquid/'strange-metal' fits to the electrical resistivity in the quantum critical magnetic regime of an unconventional superconductor |
| topic | Superconductivity Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2604.14952 |