Magnetic properties of the 2D t-t'-Hubbard model

TL;DR

This study investigates the magnetic phase transitions in the 2D t-t'-Hubbard model using slave-boson theory, revealing phase boundaries, magnetic moments, and electron-hole asymmetry consistent with quantum Monte Carlo data.

Contribution

It provides a detailed phase diagram and magnetic property analysis of the 2D t-t'-Hubbard model, highlighting the effects of t' and doping on magnetic phases.

Findings

First-order paramagnetic to antiferromagnetic transition at finite U_c(t'/t)

Dependence of magnetic moments on U/t and t'/t

t'-induced electron-hole asymmetry and phase stability at U=0

Abstract

The two-dimensional (2D) t-t'-Hubbard model is studied within the slave-boson (SB) theory. At half-filling, a paramagnetic to antiferromagnetic phase transition of first order at a finite critical interaction strength U_c(t'/t) is found. The dependences on U/t and t'/t of the sublattice magnetization and of the local magnetic moment are calculated. Our results reasonably agree with recent (Projector) Quantum Monte Carlo data. The SB ground-state phase diagram reveals a t'-induced electron-hole asymmetry, and, depending on the ratio t'/t, the antiferromagnetic or ferromagnetic phases are stable down to U=0 at a critical hole doping.