Schwinger boson mean-field theory of the kagome Heisenberg antiferromagnet with Dzyaloshinskii-Moriya interactions

Mondal, Kallol; Kadolkar, Charudatt

doi:10.1103/physrevb.95.134404

Cited by 12 publications

(24 citation statements)

References 31 publications

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“…The SBMFT (Schwinger boson mean-field theory) has been proven to be effective in describing the ordered and disordered phases of interacting quantum spins [38][39][40][41]. It has been applied to the Heisenberg models on different lattices such as the square [42], triangular [43,44] and kagomé lattices [43][44][45][46][47][48]. Here, we formulate the SBMFT for the Hida model of Eq.…”

Section: Schwinger Boson Mean-field Theorymentioning

confidence: 99%

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Spontaneous dimerization and moment formation in the Hida model of the spin-1 kagome antiferromagnet

Ghosh

Kumar

2018

Phys. Rev. B

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The Hida model, defined on honeycomb lattice, is a spin-1/2 Heisenberg model of aniferromagnetic hexagons (with nearest-neighbor interaction, JA > 0) coupled via ferromagnetic bonds (with exchange interaction, JF < 0). It applies to the spin-gapped organic materials, m−MPYNN · X (for X =I, BF 4 , ClO 4 ), and for |JF | JA, it reduces to the spin-1 kagomé Heisenberg antiferromagnet (KHA). Motivated by the recent finding of trimerized singlet (TS) ground state for spin-1 KHA, we investigate the evolution of the ground state of Hida model from weak to strong JF /JA using mean-field triplon analysis and Schwinger boson mean-field theory. Our triplon analysis of Hida model shows that its uniform hexagonal singlet (HS) ground state (for weak JF /JA) gives way to the dimerized hexagonal singlet (D-HS) ground state for |JF |/JA 1.26 (which for strong JF /JA approaches the TS state). From the Schwinger boson calculations, we find that the evolution from the uniform HS phase for spin-1/2 Hida model to the TS phase for spin-1 KHA happens through two quantum phase transitions: 1) the spontaneous dimerization transition at JF /JA ∼ −0.28 from the uniform HS to D-HS phase, and 2) the moment formation transition at JF /JA ∼ −1.46, across which the pair of spin-1/2's on every FM bond begins to express as a bound moment that tends to spin-1 for large negative JF 's. The TS ground state of spin-1 KHA is thus adiabatically connected to the D-HS ground state of the Hida model. Our calculations imply that the m−MPYNN · X salts realize the D-HS phase at low temperatures, which can be ascertained through neutron diffraction.

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Section: Schwinger Boson Mean-field Theorymentioning

confidence: 99%

“…We present here a Schwinger boson mean-field study of the KHA. Although quite a few different SBMFT studies of KHA have been done before [43][44][45][46][47][48], but they…”

Section: Appendix A: the Sbmft Of Spin-s Kagomé Heisenberg Antiferrommentioning

confidence: 99%

Spontaneous dimerization and moment formation in the Hida model of the spin-1 kagome antiferromagnet

Ghosh

Kumar

2018

Phys. Rev. B

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“…Such RMOs can be constructed for any models on any lattice and hence a general method to construct classical magnetic orders. It turns out that these states are a good candidate as a variational state to study the ground-state phase diagram for many spin systems [11][12][13][14] . It also provides useful insights into the couplings present in a magnetic material by comparing the magnetic correlation where the range or strength of the interactions is not known.…”

Section: Discussionmentioning

confidence: 99%

Regular magnetic orders in triangular and kagome lattices

Mondal,

Kadolkar

2021

Preprint

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We investigate the possible regular magnetic order (RMO) for the spin models with global O(3) spin rotation, based on a group theoretical approach for triangular and kagome lattices. The main reason to study these RMOs is that they are good variational candidates for the ground states of many specific models. In this work, we followed the prescription introduced by Messio et al. (L. Messio, C. Lhuillier, and G. Misguich, Phys. Rev. B, 2011, 83, 184401) for the p6m group and extended their work for different subgroups of p6m, i.e., p6, p3, p3m1, and p31m. We have listed all the possible regular magnetic orders for kagome and triangular lattices, which fall into the category of these groups. We calculate the energy and the spin structure factors for each of these states.

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“…It is quite a significant result in the sense that despite any spin-splitting interaction like spin-orbit coupling, a noticeable degree of spin polarization is achieved just by choosing a specific spin configuration. Such a spin orientation in kagome lattice are dubbed as Q = 0 configuration (Q is known as magnetic wave vector), are already explored extensively [70][71][72][73] and appear in many realistic materials even at room temperature 18,[74][75][76][77][78] . In summary, we can say that these types of spin configurations induce the same spin-splitting effect by breaking the spin rotational symmetry, analogous to the spin-orbit coupling.…”

Section: A Spin-resolved Transmission Coefficients and Currents Polar...mentioning

confidence: 99%

Spin-dependent transport in a driven noncolinear antiferromagnetic fractal network

Mondal,

Ganguly,

Maiti

2021

Preprint

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Noncolinear magnetic texture breaks the spin-sublattice symmetry which gives rise to a spinsplitting effect. Inspired by this, we study the spin-dependent transport properties in a noncolinear antiferromagnetic fractal structure, namely, the Sierpinski Gasket (SPG) triangle. We find that though the spin-up and spin-down currents are different, the degree of spin polarization is too weak. Finally, we come up with a proposal, where the degree of spin polarization can be enhanced significantly in the presence of a time-periodic driving field. Such a prescription of getting spin-filtering effect from an unpolarized source in a fractal network is completely new to the best of our knowledge. Starting from a higher generation of SPG to smaller ones, the precise dependencies of driving field parameters, spin-dependent scattering strength, interface sensitivity on spin polarization are critically investigated. The spatial distribution of spin-resolved bond current density is also explored. Interestingly, our proposed setup exhibits finite spin polarization for different spin-quantization axes. Arbitrarily polarized light is considered and its effect is incorporated through Floquet-Bloch ansatz. All the spin-resolved transport quantities are computed using Green's function formalism following the Landauer-Büttiker prescription. The present work brings forth new insights into spintronic properties of noncolinear antiferromagnetic SPG and should entice the AFM spintronic community to explore other fractal structures with the possibility of unconventional features.

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Schwinger boson mean-field theory of the kagome Heisenberg antiferromagnet with Dzyaloshinskii-Moriya interactions

Cited by 12 publications

References 31 publications

Spontaneous dimerization and moment formation in the Hida model of the spin-1 kagome antiferromagnet

Spontaneous dimerization and moment formation in the Hida model of the spin-1 kagome antiferromagnet

Regular magnetic orders in triangular and kagome lattices

Spin-dependent transport in a driven noncolinear antiferromagnetic fractal network

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