Paramagnons and high-temperature superconductivity in a model family of cuprates

Abstract

Cuprate superconductors have the highest critical temperatures (Tc) at ambient pressure, yet a consensus on the superconducting mechanism remains to be established. Finding an empirical parameter that limits the highest reachable Tc can provide crucial insight into this outstanding problem. Here, in the first two Ruddlesden-Popper members of the model Hg-family of cuprates, which are chemically nearly identical and have the highest Tc among all cuprate families, we use inelastic photon scattering to reveal that the energy of magnetic fluctuations may play such a role. In particular, we observe the single-paramagnon spectra to be nearly identical between the two compounds, apart from an energy scale difference of ~30% which matches their difference in Tc. The empirical correlation between paramagnon energy and maximal Tc is further found to extend to other cuprate families with relatively high Tc’s, hinting at a fundamental connection between them.

Spin singlet and quasiparticles excitations in cuprate superconductors

“…4 (d) that the energy of the SSE and the anti-nodal SC gap exhibit the same trend i.e: a decreasing with doping. However, they are not proportional to each other with doping as suggested in earlier studies [18,21,23]. We find that the 2∆ an sc 2∆sse ratio versus doping ((black square in Fig.…”

“…In the past, most of the Raman studies were focused on the spin singlet excitation (also called two-magnon) in cuprates. In particular, its relationship with the number of carriers or its interplay with the SC gap and its link to the pseudogap were investigated [15][16][17][18][19][20][21][22][23]. How-ever, these studies were severely limited by the range of doping (above p = 0.1 and below p = 0.20), which led to believe that first, the energy scale of the pseudogap phase, ∆ pg (p) and the one of the maximum amplitude of the superconducting gap, ∆ max sc (p) are the same or very close to each other and secondly, that the energy scale of the spin singlet excitation, ∆ sse (p) and the one of ∆ max sc (p) are proportional each other as a function of doping.…”

Mechanism of superconductivity in the Hubbard model at intermediate interaction strength

“… 35 finds good quantitative agreement between the spectral function computed from conventional spin fluctuation theory with magnetic susceptibility measured by inelastic neutron scattering and the spectral function measured from angle-resolved photoemission spectroscopy in the superconducting phase of YBa 2 Cu 3 O . Inelastic photon scattering experiments ( 36 ) on Hg1201 and Hg1212 infer that the superconducting temperature T c can be determined by the strength of the magnetic interactions (paramagnon signals), supporting the theory of magnetically mediated high-temperature superconductivity. Other experiments suggest a relation between superconductivity and charge density wave ( 37 ) or that the pseudogap and superconductivity may have different origins ( 38 ).…”

Magnetotransport signatures of antiferromagnetism coexisting with charge order in the trilayer cuprate HgBa2Ca2Cu3O8+δ

“…All of the above considerations strongly suggest a magnetic pairing mechanism for cuprates. In Hg1223, the clean nature and the absence of buckling of the inner CuO 2 plane support the idea that the antiferromagnetic interaction J is large, leading to higher T c 25,37 . Could the presence of charge order in the OPs be a consequence of charge imbalance and / or of out-of-plane disorder?…”