Probing the Strange Metal phase of a cuprate with nuclear magnetic resonance. – (Benjamin Costarella / LNCMI / Seminar). – 22/01/2026, 14H

Seminar LNCMI

Benjamin Costarella , 1st year PhD student of Marc-Henri Julien

Seminar LNCMI, 22/01/2026, 14H, Visio

Abstract
Cuprates (high-temperature superconductors) host in their phase diagram a so-called strange metal regime at doping levels beyond the pseudogap phase.
In this regime, the electrical resistivity is linear in temperature down to the lowest temperatures, in contrast with the quadratic dependence in conventional metals. [1]

The spin fluctuations in the strange metal regime have been sparsely investigated, and the two nuclear magnetic resonance (NMR) studies in the litterature [2,3] are partly contradictory, hindering a coherent picture of the strange metal phase.

Here, we probe the low-energy spin fluctuations in the cuprate La1.75Sr0.25CuO4 using NMR and high magnetic fields to suppress superconductivity. Our results uncover a divergent dynamical spin susceptibility at low frequency χ′′ (Q,ω→0) not captured in earlier studies, pointing to a possible connection between low-energy spin dynamics and the strange metal phenomenology. »

[1] Cooper et al. Science, 323, 5914. pp. 603-607 (2009)
[2] Ohsugi et al. JPSJ, 63, 2, pp. 700-715 (1993)
[3] Itoh et al. JPSJ, 67, 9, pp. 3018-3020 (1998)

Lien Zoom : https://univ-grenoble-alpes-fr.zoom.us/j/94228207316?pwd=khTdznxeFy1ZUYkYftQ0QSox6Fz3iK.1