The Hubbard model in strong magnetic field: Low-frequency quantum oscillations due to strong electron correlations

TL;DR

This paper investigates how strong electron correlations in the 2D Hubbard model under a magnetic field cause low-frequency quantum oscillations in the density of states, with frequencies varying significantly with doping levels.

Contribution

It provides a theoretical analysis of quantum oscillations in the Hubbard model, highlighting the impact of electron correlations and Landau subband contributions on oscillation frequencies.

Findings

Density of states oscillates with magnetic field

Oscillation frequency increases with deviation from half-filling

Frequency matches experimental observations in yttrium cuprates

Abstract

The density of states of the two-dimensional fermionic Hubbard model in the perpendicular homogeneous magnetic field is calculated using the strong coupling diagram technique. The density of states at the Fermi level as a function of the inverse magnetic induction oscillates, and the frequency of these oscillations increases by an order of magnitude with the change of the deviation from half-filling from small to moderate values. This frequency variation is caused by the change of Landau subbands contributing to the density -- in the former case they are at the periphery of the Landau spectrum, while in the latter case the dominant contribution is provided by bands near its center. With changing induction these groups of bands behave differently. For small deviations from half-filling the calculated oscillation frequency is comparable to that observed in quantum oscillation experiments in yttrium cuprates.