{"id":23916,"date":"2025-10-17T10:05:21","date_gmt":"2025-10-17T08:05:21","guid":{"rendered":"https:\/\/lncmi.cnrs.fr\/?p=23916"},"modified":"2025-10-17T10:14:06","modified_gmt":"2025-10-17T08:14:06","slug":"impact-of-low-energy-spin-fluctuations-on-the-strange-metal-in-a-cuprate-superconductor","status":"publish","type":"post","link":"https:\/\/lncmi.cnrs.fr\/en\/news\/impact-of-low-energy-spin-fluctuations-on-the-strange-metal-in-a-cuprate-superconductor\/","title":{"rendered":"Impact of low-energy spin fluctuations on the strange metal in a cuprate superconductor"},"content":{"rendered":"\n

Strange metals \u2013 which exhibit unusual properties such as a resistivity that scales linearly with temperature \u2013 challenge our understanding of charge transport in metals. A general and puzzling feature of the strange metal is a linear-in-T<\/em> resistivity existing over a wide region of the phase diagram in the limit of low temperature. In contrast, linear resistivity down to the lowest T<\/em> is observed in quantum critical metals, but only at a singular parameter in the phase diagram. A common ingredient for theories of strange metals is often the existence of a low energy degree of freedom that can effectively couple to charge carriers down to the lowest T<\/em>. In high-T<\/em>c<\/sub> cuprate superconductors, the nature and origin of these low-lying excitations remains elusive.<\/p>\n\n\n\n

We use fields as high as 86 T to explore the physics of strange metals in the cuprate superconductor La2-x<\/sub>Srx<\/sub>CuO4 <\/sub>(LSCO). Close to the critical doping of the pseudogap p<\/em>* = 0.19, we discover that T<\/em>-linear resistivity exists down to the lowest T<\/em> over an extended range of magnetic field between 60 T and 70 T or so, and disappears above (see Fig. 1a). Indeed, above 70 T, a spin glass phase gradually appears and causes the end of strange metallicity, as shown schematically in the phase diagram of Fig. 1b. In the region where low T<\/em> magnetic fluctuations exist, as demonstrated by previous NMR and ultrasound measurements, linear-in-T<\/em> resistivity appears over an extended range of magnetic field (green area in Fig. 1b). Our results show that the strange metal can be controlled with a field, via spin dynamics, and that the strange metal phase is closely linked to low energy magnetic fluctuations that persist at the lowest temperatures.<\/p>\n\n\n\n

We show that the field-dependent magnetism drives the magnetoresistance. Resistivity upturns, a signature of the metal-insulator crossover of LSCO, appear at low temperatures in the spin glass phase. This shows that the metal-insulator crossover of LSCO is linked to the freezing of spins.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Figure<\/strong> 1<\/strong>: a) Resistivity of LSCO p<\/em>= 0.188, near the pseudogap critical doping, as a function of temperature at various magnetic fields. Dashed lines are fit to the data. b) False color plot of the exponent n of the temperature dependent in-plane resistivity \u03c1(T<\/em>) = \u03c10<\/sub> + aT<\/em>n <\/sup>for LSCO p<\/em> = 0.188. It is obtained from interpolation of (dln(\u03c1(T<\/em>)-\u03c10<\/sub>)\/dlnT<\/em>) calculated for different magnetic fields. The white area corresponds to the superconducting phase and the resistive transition. \u03c10<\/sub> is the residual resistivity extrapolated to T<\/em>=0 from linear fits as shown in panel a.<\/p>\n\n\n\n

Reference :<\/strong> Impact of low-energy spin fluctuations on the strange metal in a cuprate superconductor
D. J. Campbell, M. Frachet, V. Oliviero, T. Kurosawa, N. Momono, M. Oda, J. Chang, D. Vignolles, C. Proust, D. LeBoeuf, Nature Physics (2025). https:\/\/doi.org\/10.1038\/s41567-025-03034-0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Strange metals \u2013 which exhibit unusual properties such as a resistivity that scales linearly with temperature \u2013 challenge our understanding of charge transport in metals. A general and puzzling feature […]<\/p>\n","protected":false},"author":1,"featured_media":23926,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[292],"tags":[],"post_folder":[],"class_list":["post-23916","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"jetpack_featured_media_url":"https:\/\/lncmi.cnrs.fr\/wp-content\/uploads\/2025\/10\/metal_cuprate_superconductor_Articles_-2.png","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/posts\/23916","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/comments?post=23916"}],"version-history":[{"count":1,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/posts\/23916\/revisions"}],"predecessor-version":[{"id":23921,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/posts\/23916\/revisions\/23921"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/media\/23926"}],"wp:attachment":[{"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/media?parent=23916"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/categories?post=23916"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/tags?post=23916"},{"taxonomy":"post_folder","embeddable":true,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/post_folder?post=23916"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}