RQMP (CPM) Seminar

Paramagnon scattering and pseudogaps from weak to strong coupling

Friedrich Krein

TU Wein

A momentum-selective suppression of spectral weight, the pseudogap, is observed in models of strongly correlated electrons and in experiments, for example, on high-temperature superconducting cuprates.

I review and compare pseudogaps induced by antiferromagnetic fluctuations (paramagnons) in the single-band Hubbard model from weak [1,2,3] to strong [4] coupling. At weak coupling paramagnon scattering is subject to the nesting condition and a pseudogap opens near so-called `hot spots' when the antiferromagnetic correlation length exceeds the thermal de Broglie wavelength [5]. This phenomenology is captured by the two-particle self-consistent (TPSC) theory [6]. I explain in detail the remarkable and contrasting features of paramagnon scattering at strong coupling. Here, the pseudogap opens on extended parts even of a frustrated Fermi surface while the correlation length remains short.

[1] Vilk PRB 55, 3870 (1997)
[2] Schäfer et al. PRX 11, 011058 (2021)
[3] Krien et al. PRB 102, 235133 (2020)
[4] Wu et al. PRB 96, 041105(R) (2017)
[5] Krien et al. arXiv:2107.06529
[6] Vilk & Tremblay J. Phys. I France 7, 1309 (1997)