Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 16: Superconductivity: Properties and Electronic Structure II
TT 16.11: Vortrag
Dienstag, 18. März 2025, 12:15–12:30, H32
Spin susceptibility in a pseudogap state with spiral magnetic fluctuations — •Paulo Forni1, Pietro M. Bonetti1,2, Henrik Müller-Groeling1, Demerio Villardi1, and Walter Metzner1 — 1Max Planck Institute for Solid State Research, D-70569 Stuttgart, Germany — 2Department of Physics, Harvard University, Cambridge MA 02138, USA
We explore the spin susceptibility in the pseudogap phase of the 2D Hubbard model by introducing spin fluctuations into a spiral magnetic state. This analysis is based on an emergent SU(2) gauge theory following the fractionalization of the electron field into a fermionic chargon, carrying charge, and a bosonic spinon, encoding its spin. Chargons are treated within the random phase approximation in a spiral state. Deep in the pseudogap phase, spin fluctuations can be captured by a gradient expansion of the spinon field, leading to a nonlinear sigma model whose stiffnesses are computed from the underlying chargon order. Our results reveal a gapped, nematic, and SU(2)-symmetric spin susceptibility with a broad spectrum of magnetic excitations. These findings align with key features of the pseudogap phenomenology in cuprates, offering a unified theoretical framework to describe its spin and charge degrees of freedom.
Keywords: Pseudogap; Hubbard model; Spiral spin fluctuations; Emergent gauge theories; Cuprate superconductors