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arXiv · 2303.15358

Comprehensive mean-field analysis of magnetic and charge orders in the two-dimensional Hubbard model

Robin Scholle·Pietro M. Bonetti·Demetrio Vilardi·Walter Metzner
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Abstract

We present an unbiased mean-field analysis of magnetic and charge orders in the two-dimensional Hubbard model on a square lattice, both at zero and finite temperatures. Unrestricted Hartree-Fock calculations on large finite lattices are complemented by solutions restricted to N\'eel and circular spiral order in the thermodynamic limit. The magnetic states are classified by a systematic scheme based on the dominant Fourier components of the spin texture. On finite lattices a whole zoo of ordering patterns appears. We show that many of these states are finite size artifacts related to the limited choice of ordering wave vectors on a finite lattice. In the thermodynamic limit only three classes of states with a relatively simple structure survive: N\'eel, circular spiral, and stripe states. Stripes involve also charge order and can be unidirectional or bidirectional, with horizontal and/or vertical orientation. We present complete phase diagrams in the plane spanned by electron density and temperature, for a moderate Hubbard interaction and various choices of the next-nearest neighbor hopping amplitude.

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Robin Scholle, Pietro M. Bonetti, Demetrio Vilardi, Walter Metzner. 2023-03-27. Comprehensive mean-field analysis of magnetic and charge orders in the two-dimensional Hubbard model. https://doi.org/10.1103/physrevb.108.035139

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