${\mu }^{+}$ Knight Shift in UTe${}_2$: Evidence for Relocalization in a Kondo Lattice

Abstract

The local magnetic susceptibility of the spin-triplet superconductor UTe${}_2$ has been investigated by positive muon (${\mu }^{+}$) Knight shift measurements in the normal state. Three distinct ${\mu }^{+}$ Knight shift components are observed for a magnetic field applied parallel to the $c$ axis. Two of these exhibit a breakdown in the linear relationship with the bulk magnetic susceptibility ($\chi$) below a temperature $T^{\ast }\sim 30$ K, which points to a gradual emergence of a correlated Kondo liquid. Below $T_{\mathrm{r}}\sim 12$ K linearity is gradually restored, indicating partial relocalization of the Kondo liquid quasiparticles. The third Knight shift component is two orders of magnitude larger, and despite the $c$-axis alignment of the external field, scales with the $a$-axis $\chi$ above $T_{\mathrm{r}}\sim 12$ K. We conjecture that this component is associated with magnetic clusters and the change in the temperature dependence of all three Knight shift components below $T_{\mathrm{r}}$ is associated with a change in magnetic correlations. Our findings indicate that prior to the onset of superconductivity the development of the itinerant heavy-electron fluid is halted by a gradual development of local U $5f$-moment fluctuations.

9 pages, 9 figures

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Cited by in corpus (4)

• Absence of Spontaneous Magnetic Fields Due to Time-Reversal Symmetry Breaking in Bulk Superconducting UTe2
• Molten Salt Flux Liquid Transport Method for Ultra Clean Single Crystals UTe2
• Relocalization of Uranium 5f Electrons in Antiferromagnetic Heavy Fermion Superconductor UPd${}_2$Al${}_3$: Insights from Angle-Resolved Photoemission Spectroscopy
• Muon Knight shift as a precise probe of the superconducting symmetry of Sr${}_2$RuO${}_4$