The Hubbard Model: A Computational Perspective

We study the magnetic and spectral properties of a single-band Hubbard model for the infinite-layer nickelate compound LaNiO2. As spatial correlations turn out to be the key ingredient for understanding its physics, we use two complementary extensions of the dynamical mean-field theory to take them into account: the cellular dynamical mean-field theory and the dynamical vertex approximation. Additionally to the systematic analysis of the doping dependence of the non-Curie-Weiss behavior of the uniform magnetic susceptibility, we provide insight into its relation to the formation of a pseudogap regime by the calculation of the one-particle spectral function and the magnetic correlation length. The latter is of the order of a few lattice spacings when the pseudogap opens, indicating a strong-coupling pseudogap formation in analogy to cuprates.

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“…For our study we use the single-band repulsive Hubbard model [22][23][24][25][26][27] on a two-dimensional square lattice:…”

Section: Model and Methodsmentioning

confidence: 99%

Magnetic Properties and Pseudogap Formation in Infinite-Layer Nickelates: Insights From the Single-Band Hubbard Model

2022

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“…For example, charge density wave (CDW), spin density wave (SDW), and d-wave superconducting (SC) orders all arise in significantly overlapping regimes of the phase diagram of the cuprate high-temperature superconductors. Moreover, a similarly delicate balance between these same ordering tendencies appears unavoidable in studies (2,3) of the Hubbard model with a repulsive U of order the bandwidth, U ∼ W .…”

Section: Superconductivity | Hubbard Model | Stripes | Doped Quantum Paramagnetmentioning

confidence: 99%

Stripe order enhanced superconductivity in the Hubbard model

Jiang

Kivelson

2021

Proc. Natl. Acad. Sci. U.S.A.

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Unidirectional (“stripe”) charge density wave order has now been established as a ubiquitous feature in the phase diagram of the cuprate high-temperature superconductors, where it generally competes with superconductivity. Nonetheless, on theoretical grounds it has been conjectured that stripe order (or other forms of “optimal” inhomogeneity) may play an essential positive role in the mechanism of high-temperature superconductivity. Here, we report density matrix renormalization group studies of the Hubbard model on long four- and six-leg cylinders, where the hopping matrix elements transverse to the long direction are periodically modulated—mimicking the effect of putative period 2 stripe order. We find that even modest amplitude modulations can enhance the long-distance superconducting correlations by many orders of magnitude and drive the system into a phase with a substantial spin gap and superconducting quasi–long-range order with a Luttinger exponent, Ksc∼1.

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“…The majority of recent progress in solving the Hubbard model has targeted ground state properties [11][12][13][14][15][16][17]. Studies at finite temperature have found fluctuating spin and charge stripes [6,18,19], but their interplay, doping dependence, and placement in the broader phase diagram have not been explored thoroughly.…”

mentioning

confidence: 99%