Physics Procedia

Effects of Diagonal Hopping on Stability of Antiferromagnetic State

H. Yokoyama, R. Sato, Shun Tamura, Masao Ogata

Published Jan 1, 2015• 5 citations

Abstract

Intrinsic stability as to phase separation of an antiferromagnetic state is studied for a strongly correlated Hubbard model with frustration (t-t’-U model) near half filling, using a variational Monte Carlo method. In the Hartree-Fock (one-body) part of the many-body trial state, band-renormalization effect, which is necessary for partly recovering the nesting condition, is introduced up to three-step hopping distance. As a result, a doped AF state for has a low energy but is unstable toward phase separation, which is consistent with previous studies. In contrast, the AF state becomes stable against phase separation for , owing to the contribution of hopping energy in diagonal directions. The doped AF states are metallic for the two values of , but exhibit contrastive behavior in the momentum distribution function in the nodal and antinodal regions.

DOI: 10.1016/j.phpro.2015.05.097

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Physics Procedia

Effects of Diagonal Hopping on Stability of Antiferromagnetic State

H. Yokoyama, R. Sato, Shun Tamura, Masao Ogata

Published Jan 1, 2015• 5 citations

Publisher

Abstract

DOI: 10.1016/j.phpro.2015.05.097

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Journal of the Physical Society of JapanOct 3, 20184 citations

\frac{t}{U}=\frac{1}{4}

The coexistence or exclusivity of

d_{x^{2} - y^{2}}

-wave superconducting (d-SC) and antiferromagnetic (AF) orders and instability toward phase separation (PS) are reconsidered for the square-lattice t–J model with the diagonal transfer (t′) term near half filling. To reliably treat the strong correlation including the local constraint of no double occupancy, we use a variational Monte Carlo method, in which the band-renormalization effect (BRE) is also incorporated. The results are compared with those recently obtained for the corresponding Hubbard model [J. Phys. Soc. Jpn. 85, 074701 (2016)]. It is found that BRE has a very strong effect on the AF order and greatly modifies the ground-state phase diagram in the t′–δ space (δ: doping rate) proposed in previous studies, especially for large |t′/t|. In a wide range of t′/t (|t′/t| ≤ 0.5) and for any underdoped δ (

\lesssim

0.15), the AF order arises for J/t = 0.3, similarly to in the Hubbard model. In contrast with the Hubbard model, however, the d-SC order also arises down to small δ in a wide range of t′/t (

\gtrsim

−0.2) and coexists with the AF order even for t′/t < 0 (type-II AF regime). Furthermore, there is no instability toward PS for any t′/t and δ for J/t = 0.3.