SO (3) nonlinear σ model for a doped quantum helimagnet

Klee, Susanne; Muramatsu, A.

doi:10.1016/0550-3213(96)00232-5

Cited by 14 publications

(9 citation statements)

References 60 publications

(112 reference statements)

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“…space independent, n k . To allow for spatial fluctuations of the spins around the spiral order, Klee and Muramatsu introduced a slowly varying field L via 32,33 S(r i )…”

Section: B Continuum Description Of Spiral Phasesmentioning

confidence: 99%

“…The continuum theory can then be found upon expressing in the lattice Heisenberg model the spin operators in terms of the n k and L fields, expanding the terms up to order a 2 and taking the limit a → 0 in the end. After integrating out the L fields, one finds an effective Hamiltonian which can be written in the classical limit in the general form 32 (again we include the factor β = T −1 into H)…”

Section: B Continuum Description Of Spiral Phasesmentioning

confidence: 99%

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Spin-glass phase of cuprates

2004

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We investigate a phenomenological model for the spin glass phase of La_{2-x}Sr_xCuO_4, in which it is assumed that holes doped into the CuO_2 planes localize near their Sr dopant, where they cause a dipolar frustration of the antiferromagnetic environment. In absence of long-range antiferromagnetic order, the spin system can reduce frustration, and also its free energy, by forming a state with an ordered orientation of the dipole moments, which leads to the appearance of spiral spin correlations. To investigate this model, a non-linear sigma model is used in which disorder is introduced via a randomly fluctuating gauge field. A renormalization group study shows that the collinear fixed point of the model is destroyed through the disorder and that the disorder coupling leads to an additive renormalization of the order parameter stiffness. Further, the stability of the spiral state against the formation of topological defects is investigated with the use of the replica trick. A critical disorder strength is found beyond which topological defects proliferate. Comparing our results with experimental data, it is found that for a hole density x > 0.02, i.e. in the entire spin glass regime, the disorder strength exceeds the critical threshold. In addition, some experiments are proposed in order to distinguish if the incommensurabilities observed in neutron scattering experiments correspond to a diagonal stripe or a spiral phase.Comment: 22 pages, 11 figures, revised version, short discussion on Li doped samples added to Sec.IV. To appear in PRB 01 January 200

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“…space independent, n k . To allow for spatial fluctuations of the spins around the spiral order, Klee and Muramatsu introduced a slowly varying field L via 32,33 S(r i )…”

Section: B Continuum Description Of Spiral Phasesmentioning

confidence: 99%

Section: B Continuum Description Of Spiral Phasesmentioning

confidence: 99%

Spin-glass phase of cuprates

2004

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“…These constants may also be obtained by a complementary calculation ab initio starting from a particular model. Many examples of these calculations exist in the literature (see for instance [15,16,17,18]). They are usually hard, require some approximations (typically Hartree-Fock or mean-field), and, of course, the outcome depends on the particular model choosen for the microscopic dynamics.…”

Section: Introductionmentioning

confidence: 99%

Effective Field Theory Approach to Ferromagnets and Antiferromagnets in Crystalline Solids

Román

Soto

1999

Int. J. Mod. Phys. B

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We present a systematic construction of effective lagrangians for the low energy and momentum region of ferromagnetic and antiferromagnetic spin waves in crystalline solids. We fully exploit the spontaneous symmetry breaking pattern SU (2) → U (1), the fact that spin waves are its associated Goldstone modes, the crystallographic space group and time reversal symmetries. We show how to include explicit SU (2) breaking terms due to spin-orbit and magnetic dipole interactions. The coupling to electromagnetic fields is also discussed in detail. For definiteness we work with the space group R3c and present our results to next to leading order.

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“…A possible representation of the local spiral order is in terms of orthonormal n k , k = 1, 2, 3, with n a k n a q = δ kq . A derivation of a continuum field theory for a spiral state from a lattice Heisenberg model can be found in [17]. Using S ij = n 1 cos(k S · r ij ) − n 2 sin(k S · r ij ) and n 3 = n 1 × n 2 , where S ij is the spin at the lattice site (i, j), k S = (π, π) + q S and q S is the IC ordering wave vector of the spiral, the effective classical Hamiltonian can be written in the formH…”

mentioning

confidence: 99%

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confidence: 99%

Topological defects and the spin glass phase of cuprates

Hasselmann¹,

Neto²,

Smith³

2001

Europhys. Lett.

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We propose that the spin glass phase of cuprates is due to the proliferation of topological defects of a spiral distortion of the antiferromagnet order. Our theory explains straightforwardly the simultaneous existence of short range incommensurate magnetic correlations and complete a-b symmetry breaking in this phase. We show via a renormalization group calculation that the collinear O(3)/O(2) symmetry is unstable towards the formation of local non-collinear correlations. A critical disorder strength is identified beyond which topological defects proliferate already at zero temperature.c EDP Sciences

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SO (3) nonlinear σ model for a doped quantum helimagnet

Abstract: A field theory describing the low-energy, long-wavelength sector of an incommensurate, spiral magnetic phase is derived from a spin-fermion model that is commonly used as a microscopic model for high-temperature superconduc-

Cited by 14 publications

References 60 publications

Spin-glass phase of cuprates

Spin-glass phase of cuprates

Effective Field Theory Approach to Ferromagnets and Antiferromagnets in Crystalline Solids

Topological defects and the spin glass phase of cuprates

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