Magnetic phase diagram of the Hubbard model in the Lieb lattice

Abstract

We study the mean-field phase diagram of the repulsive Hubbard model in the Lieb lattice. Far from half-filling, the most stable phases are paramagnetism for low on-site interaction $U/t$ and ferromagnetism for high $U/t$, as in the case of the mean-field phase diagram of the square lattice Hubbard model obtained by Dzierzawa [\onlinecite{Dzierzawa1992}]. At half-filling, the ground state was found to be ferrimagnetic [a $(\pi ,\pi )$ spiral phase], in agreement with a theorem by Lieb [\onlinecite{Lieb1989}]. The total magnetization approaches Lieb's prediction as $U/t$ becomes large. As we move away from half-filling, this ferrimagnetic phase becomes a $(q_1,q_1)$ spiral phase with $q_1\approx \pi$ and then undergoes a series of first-order phase transitions, $(q_1,q_1)\to (q_1,q_2)\to (q_1,0)$, with $q_2\approx \pi /2$, before becoming ferromagnetic at large $U/t$ or paramagnetic at low $U/t$.

6 pages, 5 figures

References in corpus (2)

• Topological Insulators on the Lieb and Perovskite Lattices
• Topological Phases for Fermionic Cold Atoms on the Lieb Lattice

Cited by in corpus (6)

• Generalized Lieb's theorem for noninteracting non-Hermitian $n$-partite tight-binding lattices
• Model studies of topological phase transitions in materials with two types of magnetic atoms
• Ground state spin and excitation energies in half-filled Lieb lattices
• Canted magnetism and ${\mathbb{Z}}_2$ fractionalization in metallic states of the Lieb lattice Hubbard model near quarter filling
• Surface magnon spectra of nodal loop semimetals
• Update of Hartree--Fock theory for Hubbard-like models