SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 29: Frustrated Magnets: General

TT 29.6: Vortrag

Mittwoch, 29. März 2023, 10:45–11:00, HSZ 201

Valence bond solid state in explicitly dimerized chain with magnetic frustration — •Jȩdrzej Wardyn¹, Satoshi Nishimoto^1,2, and Cliò Efthimia Agrapidis³ — ¹IFW Dresden, 01069 Dresden, Germany — ²TU Dresden, 01062 Dresden, Germany — ³Faculty of Physics, University of Warsaw, Pasteura 5, 02093 Warsaw, Poland;

We consider the spin-1/2 dimerized frustrated ferromagnetic (FM) J₁−J₁′−J₂ model, with J₁,J₁′<0 FM first neighbours coupling and J₂>0 antiferromagnetic second neighbors coupling. This model serves as a minimal model for LiCuSbO₄ and Rb₂Cu₂Mo₃O₁₂. We introduce the frustration parameter J₂/|J₁|=α and the dimerization parameter J₁′/J₁=β. There are two special limits of dimerization: fully dimerized at β=0 and the undimerized J₁−J₂ model at β=1. Earlier studies have identified phases featured in the special limits as valence bond solid with a finite spin gap for β=1 and a Haldane-like state for β=0. For our model, the spin gap and phase diagram was investigated in a 2017 study by Agrapidis et al. [1]. Thanks to new insight, we revisit these results with applying new boundary conditions, which allow us to correctly estimate the spin gap which was previously underestimated. We compute the spin gap, the string order parameter (SOP), and dimer-dimer correlations using the density matrix renormalization group method (DMRG). We prove that the model features a VBS state. Our results allow us to determine this state as D₃-VBS state adiabatically connected to the Haldane-like state in the limit of β=0.

[1] C. E. Agrapidis et al., Phys. Rev. B, 95, 220404 (2017).