Static and Dynamical Characterization of Ground State Phases Induced by Frustration and Magnetic Field in the Spin-1 Orthogonal Dimer Chain

TL;DR

This study uses DMRG to analyze the ground state phases of a spin-1 orthogonal dimer chain under frustration and magnetic field, revealing complex phases with Haldane-like, fragmented, and clustered characteristics.

Contribution

The paper introduces a new basis transformation for DMRG that enhances symmetry implementation and reduces entanglement bias, enabling detailed phase diagram mapping.

Findings

Identification of multiple ground state phases with distinct static properties.

Observation of Haldane chain-like behavior in certain phases.

Analysis of low-energy dynamics through dynamic structure factor calculations.

Abstract

The spin-$1$ orthogonal dimer chain is investigated using the Density Matrix Renormalization Group (DMRG) algorithm. A transformation to a basis that uses the local eigenstates of the orthogonal dimers, while retaining the local spin states for the parallel spins, allows for more effective implementation of the symmetries, as well as mitigating the entanglement bias of DMRG. A rich ground state phase diagram is obtained in the parameter space spanned by the ratio of inter- to intra-dimer interaction (which measures the degree of frustration) and an external magnetic field. Some ground state phases exhibit effective Haldane chain character, whereas others exhibit fragmentation of the ground state wavefunction, or clustering. The phases are characterized by their static properties, including (local) spin quantum number, entanglement entropy, and the spin-spin correlation function. Detailed characterization of a carefully selected set of representative states is presented. The static properties are complemented by exploring the low-energy dynamics through the calculation of the dynamic structure factor. The results provide crucial insight into the emergence of complex ground state phases from the interplay between strong interactions, geometric frustration, and external magnetic field for interacting S=1 Heisenberg spins.