2007/09/17 by S. Moukouri, Moukouri, S.
Computer Science · Engineering · Physics and Astronomy · #FOS: Physical sciences #Material Science and Thermodynamics #Nonlinear Dynamics and Pattern Formation #Strongly Correlated Electrons (cond-mat.str-el) #Theoretical and Computational Physics
paper · pdf · doi:10.48550/arxiv.0709.2688
openalex publication_date 2007/09/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
I use an improved version of the two-step density matrix renormalization group method to study ground-state properties of the 2D Heisenberg model on the checkerboard lattice. In this version the Hamiltonian is projected on a tensor product of two-leg ladders instead of chains. This allows investigations of 2D isotropic models. I show that this method can describe both the magnetically disordered and ordered phases. The ground-state phases of the checkerboard model as J2 increases are: (i) Néel with Q=(π,π), (ii) a valence bond crystal (VBC) of plaquettes, (iii) Néel with Q=(π/2,π), and (iv) a VBC of crossed dimers. In agreement with previous results, I find that at the isotropic point J2=J1, the ground state is made of weakly interacting plaquettes with a large gap Δ≈ 0.67 J1 to triplet excitations.