Failed superconductivity in a Mott spin liquid material

Fuente: arXiv
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Main Authors: Wang, Yuxin, Dobrosavljević, Vladimir, Choi, Eun Sang, Saito, Yohei, Kawamoto, Atsushi, Pustogow, Andrej, Dressel, Martin, Popović, Dragana
Format: Preprint
Published: 2025
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author Wang, Yuxin
Dobrosavljević, Vladimir
Choi, Eun Sang
Saito, Yohei
Kawamoto, Atsushi
Pustogow, Andrej
Dressel, Martin
Popović, Dragana
author_facet Wang, Yuxin
Dobrosavljević, Vladimir
Choi, Eun Sang
Saito, Yohei
Kawamoto, Atsushi
Pustogow, Andrej
Dressel, Martin
Popović, Dragana
contents A central challenge for understanding unconventional superconductivity in most strongly correlated electronic materials is their complicated band structure and presence of competing orders. In contrast, quasi-two-dimensional organic spin liquids are single-band systems with superconductivity arising near the bandwidth-tuned Mott metal-insulator transition in the absence of other orders. Here, we study chemically substituted $κ$-organics in which superconducting fluctuations emerge in the phase coexistence region between the Mott insulator and the Fermi liquid. Using magnetotransport and ac susceptibility measurements, we find that global superconductivity fails to set in as temperature $T\rightarrow 0$. Our results indicate instead the presence of superconducting domains embedded in the metallic percolating cluster that undergo a magnetic field-tuned quantum superconductor-to-metal phase transition. Surprisingly, albeit consistent with the percolation picture, universal conductance fluctuations are seen at high fields in macroscopic samples. The observed interplay of the intrinsic inhomogeneity and quantum phase fluctuations provides a new insight into failed superconductivity, a phenomenon seen in various conventional and unconventional superconductors, including cuprates.
format Preprint
id arxiv_https___arxiv_org_abs_2507_10832
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Failed superconductivity in a Mott spin liquid material
Wang, Yuxin
Dobrosavljević, Vladimir
Choi, Eun Sang
Saito, Yohei
Kawamoto, Atsushi
Pustogow, Andrej
Dressel, Martin
Popović, Dragana
Superconductivity
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
A central challenge for understanding unconventional superconductivity in most strongly correlated electronic materials is their complicated band structure and presence of competing orders. In contrast, quasi-two-dimensional organic spin liquids are single-band systems with superconductivity arising near the bandwidth-tuned Mott metal-insulator transition in the absence of other orders. Here, we study chemically substituted $κ$-organics in which superconducting fluctuations emerge in the phase coexistence region between the Mott insulator and the Fermi liquid. Using magnetotransport and ac susceptibility measurements, we find that global superconductivity fails to set in as temperature $T\rightarrow 0$. Our results indicate instead the presence of superconducting domains embedded in the metallic percolating cluster that undergo a magnetic field-tuned quantum superconductor-to-metal phase transition. Surprisingly, albeit consistent with the percolation picture, universal conductance fluctuations are seen at high fields in macroscopic samples. The observed interplay of the intrinsic inhomogeneity and quantum phase fluctuations provides a new insight into failed superconductivity, a phenomenon seen in various conventional and unconventional superconductors, including cuprates.
title Failed superconductivity in a Mott spin liquid material
topic Superconductivity
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
url https://arxiv.org/abs/2507.10832