Character of frustration on magnetic correlation in doped Hubbard model

TL;DR

This study investigates how magnetic correlations in a doped Hubbard model on a 2D anisotropic triangular lattice are affected by frustration and doping, revealing a complex phase diagram with changing magnetic orders.

Contribution

It provides a detailed non-perturbative analysis of the magnetic phase diagram considering frustration and doping effects in the Hubbard model.

Findings

Increasing frustration shifts the wave vector of maximum spin correlation.

Doping suppresses antiferromagnetic correlation and promotes 120° order.

Rich magnetic phase diagram depends on frustration and electron doping levels.

Abstract

The magnetic correlation in the Hubbard model on a two-dimensional anisotropic triangular lattice is studied by using the determinant quantum Monte Carlo method. Around half filling, it is found that the increasing frustration $t'/t$ could change the wave vector of maximum spin correlation along ($\pi,\pi$)$\rightarrow$($\pi,\frac{5\pi}{6}$)$\rightarrow$($\frac{5\pi}{6},\frac{5\pi}{6}$)$\rightarrow$ ($\frac{2\pi}{3},\frac{2\pi}{3}$), indicating the frustration's remarkable effect on the magnetism. In the studied filling region <n>=1.0-1.3, the doping behaves like some kinds of {\it{frustration}}, which destroys the $(\pi,\pi)$ AFM correlation quickly and push the magnetic order to a wide range of the $(\frac{2\pi}{3},\frac{2\pi}{3})$ $120^{\circ}$ order when the $t'/t$ is large enough. Our non-perturbative calculations reveal a rich magnetic phase diagram over both the frustration and electron doping.