Magnetic and nonmagnetic phases in doped AB2 t-J Hubbard chains

TL;DR

This paper explores the complex phase diagram of doped AB2 t-J chains, revealing various magnetic and quantum phases, and compares these findings with other lattice structures using advanced numerical methods.

Contribution

It provides a detailed analysis of the phase diagram of doped AB2 t-J chains, highlighting new magnetic and quantum phases, and compares these with other lattice geometries.

Findings

Identification of ferrimagnetic, incommensurate, RVB, and Nagaoka states

Observation of phase separation and Luttinger liquid behavior

Verification of findings across different lattice types

Abstract

We discuss the rich phase diagram of doped AB2 $t-J$ chains by using data from density matrix renormalization group and exact diagonalization techniques. The $J$ vs $\delta$ (hole doping) phase diagram exhibits regions of itinerant ferrimagnetism, incommensurate, resonating valence bond and Nagaoka states, phase separation, and Luttinger liquid (LL) physics. Several features are highlighted, such as the modulated ferrimagnetic structure, the occurrence of Nagaoka spin polarons in the underdoped regime and small values of $J=4t^2/U$, where $t$ is the first-neighbor hopping amplitude and $U$ is the on-site repulsive Coulomb interaction, incommensurate structures with nonzero magnetization, and strong-coupling LL physics in the high-doped regime. We also verify that relevant findings are in agreement with the corresponding findings in square and n-leg ladder lattices. In particular, we mention the instability of Nagaoka ferromagnetism against $J$ and $\delta$.