Quantum Fluctuation-induced Phase Transition in<i>S</i>=1/2 XY-like Heisenberg Antiferromagnets on the Triangular Lattice

Yoshikawa, Shingo; Okunishi, Kouichi; Senda, Makoto; Miyashita, Seiji

doi:10.1143/jpsj.73.1798

Cited by 25 publications

(30 citation statements)

References 26 publications

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“…In addition to the TST, we have also studied the 1/3 magnetization plateau for L y = 6 cylinders, see Figure 25. Close to the isotropic limit, R 1, the plateau width is only slightly changed by the increase in width from L y = 3 to L y = 6, and its value ∆h ≈ 0.7J agrees well with previous numerical studies 10,39,51,52 . This trend in width is consistent with our picture that for small R the phases proximate to the plateau are commensurate planar ordered ones in the 2d limit.…”

Section: A Implications For Two Dimensionssupporting

confidence: 90%

Ground states of spin-12triangular antiferromagnets in a magnetic field

Chen

Jiang

et al. 2013

Phys. Rev. B

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We use a combination of numerical density matrix renormalization group (DMRG) calculations and several analytical approaches to comprehensively study a simplified model for a spatially anisotropic spin-1/2 triangular lattice Heisenberg antiferromagnet: the three-leg triangular spin tube (TST). The model is described by three Heisenberg chains, with exchange constant J, coupled antiferromagnetically with exchange constant J along the diagonals of the ladder system, with periodic boundary conditions in the shorter direction. Here we determine the full phase diagram of this model as a function of both spatial anisotropy (between the isotropic and decoupled chain limits) and magnetic field. We find a rich phase diagram, which is remarkably dominated by quantum states -the phase corresponding to the classical ground state appears only in an exceedingly small region. Among the dominant phases generated by quantum effects are commensurate and incommensurate coplanar quasi-ordered states, which appear in the vicinity of the isotropic region for most fields, and in the high field region for most anisotropies. The coplanar states, while not classical ground states, can at least be understood semiclassically. Even more strikingly, the largest region of phase space is occupied by a spin density wave phase, which has incommensurate collinear correlations along the field. This phase has no semiclassical analog, and may be ascribed to enhanced one-dimensional fluctuations due to frustration. Cutting across the phase diagram is a magnetization plateau, with a gap to all excitations and "up up down" spin order, with a quantized magnetization equal to 1/3 of the saturation value. In the TST, this plateau extends almost but not quite to the decoupled chains limit. Most of the above features are expected to carry over to the two dimensional system, which we also discuss. At low field, a dimerized phase appears, which is particular to the one dimensional nature of the TST, and which can be understood from quantum Berry phase arguments.

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Section: A Implications For Two Dimensionssupporting

confidence: 90%

Ground states of spin-12triangular antiferromagnets in a magnetic field

Chen

Jiang

et al. 2013

Phys. Rev. B

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“…33 To clarify this issue, one could calculate numerically the chirality correlator ͗ 0 z n z ͘ in the limit n → ϱ above the cusp singularity. For spin-1 2 chain, such a correlator was calculated only for very short distances 34 and indicated emergence of at least shortrange chirality correlations for h directly below the saturation field h s . The chiral phase should be able to survive finite temperature effects since it involves breaking of the discrete Z 2 symmetry.…”

Section: Discussionmentioning

confidence: 99%

Field-induced chiral phase in isotropic frustrated spin chains

2005

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“…Since the seminal work by Kawamura and Miyashita [20], it has been known that the simplest model of TLAFs with isotropic Heisenberg interactions possesses an accidental continuous degeneracy of the classical ground state for finite magnetic fields. Past theoretical efforts have established that quantum (or thermal) fluctuations lift the classical degeneracy and select a magnetization process whose magnetization curve exhibits a plateau at one-third of the saturation magnetization [20][21][22][23][24][25][26]. However, such a one-third magnetization plateau has been actually observed only in a few TLAF materials [11,27,28].…”

Section: Introductionmentioning

confidence: 99%

Exact diagonalization and cluster mean-field study of triangular-lattice XXZ antiferromagnets near saturation

et al. 2017

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Quantum magnetic phases near the magnetic saturation of triangular-lattice antiferromagnets with XXZ anisotropy have been attracting renewed interest since it has been suggested that a nontrivial coplanar phase, called the π-coplanar or Ψ phase, could be stabilized by quantum effects in a certain range of anisotropy parameter J/Jz besides the well-known 0-coplanar (known also as V ) and umbrella phases. Recently, Sellmann et al. [Phys. Rev. B 91, 081104(R) (2015)] claimed that the π-coplanar phase is absent for S = 1/2 from an exact-diagonalization analysis in the sector of the Hilbert space with only three down-spins (three magnons). We first reconsider and improve this analysis by taking into account several low-lying eigenvalues and the associated eigenstates as a function of J/Jz and by sensibly increasing the system sizes (up to 1296 spins). A careful identification analysis shows that the lowest eigenstate is a chirally antisymmetric combination of finite-size umbrella states for J/Jz 2.218 while it corresponds to a coplanar phase for J/Jz 2.218. However, we demonstrate that the distinction between 0-coplanar and π-coplanar phases in the latter region is fundamentally impossible from the symmetry-preserving finite-size calculations with fixed magnon number. Therefore, we also perform a cluster mean-field plus scaling analysis for small spins S ≤ 3/2. The obtained results, together with the previous large-S analysis, indicate that the π-coplanar phase exists for any S except for the classical limit (S → ∞) and the existence range in J/Jz is largest in the most quantum case of S = 1/2.

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Quantum Fluctuation-induced Phase Transition inS=1/2 XY-like Heisenberg Antiferromagnets on the Triangular Lattice

Cited by 25 publications

References 26 publications

Ground states of spin-12triangular antiferromagnets in a magnetic field

Ground states of spin-12triangular antiferromagnets in a magnetic field

Field-induced chiral phase in isotropic frustrated spin chains

Exact diagonalization and cluster mean-field study of triangular-lattice XXZ antiferromagnets near saturation

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