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MA: Fachverband Magnetismus

MA 10: Electron Theory of Magnetism and Correlations/Other Theory

MA 10.8: Vortrag

Montag, 18. März 2024, 17:00–17:15, EB 107

Paramagnons in Na_xCa_2−xCuO₂Cl₂ from a Quantum Cluster Approach using Matrix-Product States — •Abhiroop Lahiri¹, Sebastian Paeckel², Thomas Köhler³, and Benjamin Lenz¹ — ¹IMPMC UMR-7590,CNRS, Sorbonne Université, Paris, France — ²Ludwig-Maximilians-Universität München, Germany — ³Uppsala Universitet, Uppsala, Sweden

In recent years, advances in the field of resonant inelastic x-ray scattering (RIXS) have rendered the measurement of paramagnons in doped cuprates feasible. In certain cases, the collective low-energy excitations seen in the RIXS map can be described to a good approximation by the dynamical spin structure factor. In this talk, we will show a comprehensive study of this quantity for a doped Hubbard-type model, tailored via ab initio simulations to the cuprate Na_xCa_2−xCuO₂Cl₂ . In our calculations, we choose different quantum clusters and employ matrix-product states (MPS) to describe the cluster wave-function. This efficient way of representing the essential part of the Hilbert space allows us to treat cluster sizes within density matrix renormalization group that go beyond the scope of standard exact diagonalization solvers. In particular, our approach is based on a recently developed band-Lanczos method optimized for the use of MPS. We finally compare our results to the literature, in particular to cluster dynamical mean-field theory calculations and RIXS measurements of the material.

Keywords: RIXS spectra; Qunatum Cluster; Hubbard Model; Matrix Product States; Dynamical Structure Factor