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MA: Fachverband Magnetismus

MA 34: Computational Magnetism I

MA 34.8: Vortrag

Mittwoch, 11. März 2026, 17:00–17:15, HSZ/0004

Forestalled phase separation as the precursor to stripe order and superconductivity — •Aritra Sinha and Alexander Wietek — Max Planck Institute for the Physics of Complex Systems

Stripe order is a key feature of the cuprate phase diagram and appears as the ground state of the two-dimensional Fermi-Hubbard and t-J models in relevant regimes. With increasing temperature, stripe and superconducting orders give way to the strange metal and pseudogap phases, whose microscopic origins remain unclear. Using advanced tensor-network simulations, we try to identify the real-space mechanisms behind this evolution. iPEPS reveals a strong peak in the uniform charge susceptibility above the stripe phase near hole doping p=0.1, sharpening on cooling. METTS simulations on finite cylinders trace this peak to fluctuating charge clusters, resembling incipient phase separation into hole-rich and hole-poor regions-ultimately prevented by stripe order at low temperature. In the doped Mott regime of the t-t’-J model, we find that fluctuating domain walls of doped holes act as precursors to superconductivity. At low T, transient mergers of hole-rich regions create larger clusters containing superconducting condensates, which gradually phase-lock upon cooling into a coherent, stripe-aligned d-wave superconductor. Together, these results suggest a unified picture where charge and pairing fluctuations evolve into stripe order and superconductivity, clarifying their intertwined roles in strongly correlated systems.

Keywords: superconductivity; Hubbard; tensor networks; finite temperature; phase separation