Combined analytical and numerical approach to study magnetization plateaux in doped quasi-one-dimensional antiferromagnets

Lamas, Carlos Alberto; Capponi, Sylvain; Pujol, Pierre

doi:10.1103/physrevb.84.115125

Cited by 19 publications

(24 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Taking the inverse Fourier transform, with the vortex current given by J V = qdr and endowing the above expression with an overall coefficient κ, the above expression corresponds to vortex current-vortex current interaction (11) in Fourier space. This is precisely equal to the topological part of Eq.…”

Section: Field Theorymentioning

confidence: 99%

Protection against a spin gap in two-dimensional insulating antiferromagnets with a Chern-Simons term

Makhfudz

Pujol

2015

Phys. Rev. B

View full text Add to dashboard Cite

We propose a novel mechanism for the protection against spin gapped states in doped antiferromagnets. It requires the presence of a Chern-Simons term that can be generated by a coupling between spin and an insulator. We first demonstrate that in the presence of this term the vortex loop excitations of the spin sector behave as anyons with fractional statistics. To generate such term, the fermions should have massive Dirac spectrum coupled to the emergent spin field of the spin sector. The Dirac spectrum can be realized by a planar spin configuration arising as the lowest-energy configuration of a square lattice antiferromagnet Hamiltonian involving a Dzyaloshinskii-Moriya interaction. The mass is provided by a combination of dimerization and staggered chemical potential. We finally show that for realistic parameters, anyonic vortex loop condensation will likely never occur and thus the spin gapped state is prevented. We also propose real magnetic materials for an experimental verification of our theory.

show abstract

Section: Field Theorymentioning

confidence: 99%

Protection against a spin gap in two-dimensional insulating antiferromagnets with a Chern-Simons term

Makhfudz

Pujol

2015

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…When we slightly move away from the condition J ′ (i) = J ′′ (i), these plateaux may remain present in the magnetization curve, whereas the jumps are smoothed. This frustration induced plateaux has been studied for S = 1/2, S = 1 and S = 3/2 ladders [30][31][32][33] The present analysis provides a simple theoretical explanation for this behavior.…”

Section: B Localized Triplonsmentioning

confidence: 95%

“…For the case of symmetrical frustration the excitations were also exactly determined and a discussion about the magnetization process [30][31][32][33] was presented. The ground state properties around the exact manifold in the parameter space were explored by means of numerical analysis, showing that these remain close to the exact case over a finite region.…”

Section: Discussion and Perspectivesmentioning

confidence: 99%

“…In higher dimensions there is an important amount of results on dimerized ground states [44][45][46][47][48] that can be used as starting point to study hole dynamics. In 2D has been recently proved that the quantum statistics of holes in a dimer background can be changed without affect the energy dispersion 49 and the density of holes has an impact on the magnetization plateaux 32 . As we start from these families of models where the ground state is a dimer covering, introducing holes in the system may result in a very interesting phase diagram.…”

Section: Discussion and Perspectivesmentioning

confidence: 99%

See 1 more Smart Citation

Dimerized ground states inspin−Sfrustrated systems

Lamas

Matera

2015

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

We study a family of frustrated anti-ferromagnetic spin-S systems with a fully dimerized ground state. Starting from the simplest case of the frustrated zig-zag spin ladder, we generalize the family to more complex geometries like tetrahedral ladders and spin tubes. After present some numerical results about the phase diagram of these systems, we show that the ground state is robust against the inclusion of weak disorder in the couplings as well as several kinds of perturbations, allowing to study some other interesting models as a perturbative expansion of the exact one. A discussion on how to determine the dimerization region in terms of quantum information estimators is also presented. Finally, we explore the relation of these results with a the case of the a 4-leg spin tube which recently was proposed as a model for the description of the compound Cu2Cl4D8C4SO2, delimiting the region of the parameter space where this model presents dimerization in its ground state.

show abstract

“…Although the converse sounds plausible, it does not hold in general. Since known counterexamples [39][40][41][42][43] are somewhat complicated, let us discuss here a simple example of noninteracting band semimetals. For noninteracting electrons, χ(µ) coincides with the density of states D(µ) per unit volume and thus χ(µ) vanishes when the dimensionality of the Fermi surface reduces, for example, at Dirac or Weyl points in 3D.…”

mentioning

confidence: 99%

Energy Gap of Neutral Excitations Implies Vanishing Charge Susceptibility

Watanabe

2017

Phys. Rev. Lett.

View full text Add to dashboard Cite

In quantum many-body systems with a U(1) symmetry, such as the particle number conservation and the axial spin conservation, there are two distinct types of excitations: charge-neutral excitations and charged excitations. The energy gaps of these excitations may be independent with each other in strongly correlated systems. The static susceptibility of the U(1) charge vanishes when the charged excitations are all gapped, but its relation to the neutral excitations is not obvious. Here we show that a finite excitation gap of the neutral excitations is, in fact, sufficient to prove that the charge susceptibility vanishes (i.e. the system is incompressible). This result gives a partial explanation on why the celebrated quantization condition n(S − mz) ∈ Z at magnetization plateaus works even in spatial dimensions greater than one.Introduction. -When do we expect a plateau in a magnetization curve? A very simple 'quantization condition' is known to explain actual experiments over wide variety of materials in one [1-4], two [5][6][7][8][9], and three [10][11][12] spatial dimensions: in spin models, a plateau appears when the zcomponent of the total spin is conserved and the magnetization per unit cell m z satisfies S − m z ∈ Z, where S is the saturation magnetization per unit cell [13][14][15][16]. (For theoretical works on specific models, see references in Ref. [16].) When the unit cell is enlarged by spontaneous breaking of translation symmetry, S and m z should be computed with respect to the 'new' unit cell. The reasoning leading to this condition is as follows. It is natural to expect a finite excitation gap in the energy spectrum at a plateau. In one-dimension, when S −m z is not an integer, one can construct a low-energy state by acting "the twist operator"Û = exp i

show abstract

Combined analytical and numerical approach to study magnetization plateaux in doped quasi-one-dimensional antiferromagnets

Cited by 19 publications

References 47 publications

Protection against a spin gap in two-dimensional insulating antiferromagnets with a Chern-Simons term

Protection against a spin gap in two-dimensional insulating antiferromagnets with a Chern-Simons term

Dimerized ground states inspin−Sfrustrated systems

Energy Gap of Neutral Excitations Implies Vanishing Charge Susceptibility

Contact Info

Product

Resources

About