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arXiv:cond-mat/0309718

Effect of one-ion L-S coupling on magnetic properties of a correlated spin-orbit system

Zu‐Jian Ying, Xi-Wen Guan, Angela Foerster, I. Roditi, Bin Chen

Published Sep 30, 2003• 1 citation
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Abstract

By introducing a basis for a novel realization of the SU(4) Lie algebra, we exactly solve a spin-orbital chain with one-ion $L$-$S$ coupling (OILSC) via the Bethe ansatz (BA) approach. In the context of different Landé $g$ factors of the spin and orbital sectors, the OILSC results in rich and novel quantum phase transitions. Some accurate analytical expressions for the critical fields are obtained. Both spin ordering and orbital ordering are found in a gapped singlet phase. The system exhibits many interesting phenomena such as nonvanishing magnetization of the singlet phase, multi-entrance of the singlet in the ground state when the field varies, unsymmetric magnetization in two-component phase and magnetization crossover for different OILSC.

DOI
10.48550/arxiv.cond-mat/0309718

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By introducing a basis for a novel realization of the SU(4) Lie algebra, we exactly solve a spin-orbital chain with one-ion LLL-SSS coupling (OILSC) via the Bethe ansatz (BA) approach. In the context of different Landé ggg factors of the spin and orbital sectors, the OILSC results in rich and novel quantum phase transitions. Some accurate analytical expressions for the critical fields are obtained. Both spin ordering and orbital ordering are found in a gapped singlet phase. The system exhibits many interesting phenomena such as nonvanishing magnetization of the singlet phase, multi-entrance of the singlet in the ground state when the field varies, unsymmetric magnetization in two-component phase and magnetization crossover for different OILSC.
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The ground-state phases of a one-dimensional SU(4) spin-orbital Hamiltonian in a generalized external field are studied on the basis of the Bethe-ansatz solution. Introducing three Land\'e g factors for spin, orbital, and their products in the SU(4) Zeeman term, we systematically discuss various symmetry breakings. The magnetization versus external field is evaluated by solving the Bethe-ansatz equations numerically. The phase diagrams corresponding to distinct residual symmetries are given by means of both numerical and analytical methods.
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We investigate ground-state properties and quantum phase transitions in the one-dimensional S=1S=1S=1 spin-orbital model relevant to cubic vanadates. Using the density-matrix renormalization group, we compute the ground-state energy, the magnetization, and the correlation functions for different values of the Hund's coupling JH{J}_{H}JH​ and the external magnetic field. It is found that the magnetization jumps at a certain critical field, which is a hallmark of the field-induced first-order phase transition. The phase transition driven by JH{J}_{H}JH​ is also of first order. We also consider how the lattice-induced ferro-type interaction between orbitals modifies the phase diagram, and discuss the results in a context of the first-order phase transition observed in YVO3{\mathrm{YVO}}_{3}YVO3​ at 77 K.