Publisher's Note: Arsenic-bridged antiferromagnetic superexchange interactions in LaFeAsO [Phys. Rev. B<b>78</b>, 224517 (2008)]

Section: Introductionmentioning

confidence: 99%

Ferromagnetism in CuFeSb: Evidence of competing magnetic interactions in iron-based superconductors

Qian

Lee

et al. 2012

“…In the parent iron pnictides, the Néel transition into a (π, 0) antiferromagnet is either preceded by or concomitant with a tetragonal-to-orthorhombic structural transition. The (π, 0) magnetic order by itself can be understood either by invoking a local moment J 1 − J 2 model [4][5][6][7][8][9][10][11] or an itinerant model with nearly nested electron and hole pockets [12][13][14] .…”

mentioning

confidence: 99%

Spin dynamics of aJ1−J2antiferromagnet and its implications for iron pnictides

Goswami

et al. 2011

Motivated by the recent observation of antiferromagnetic correlations in the paramagnetic phase of iron pnictides, we study the finite temperature spin dynamics of a two dimensional J1 − J2 antiferromagnet. We consider the paramagnetic phase in the regime of a (π, 0) collinear ground state, using the modified spin wave theory. Below the mean field Ising transition temperature, we identify short-range anisotropic antiferromagnetic correlations. We show that the dynamical structure factor S(q, ω) contains elliptic features in the momentum space, and determine its variation with temperature and energy. Implications for the spin-dynamical experiments in the iron pnictides are discussed.

“…The most famous example is the spin-driven nematicity that occurs in the iron-based superconductors. The single-stripe (SS) magnetic ground state [2,3] breaks both continuous spin rotation symmetry and discrete C 4 lattice rotation symmetry, allowing a nematic phase, breaking only the rotation symmetry, to develop above the magnetic transition where the spin-rotation symmetry is broken [4]. Essentially, this nematic order can be understood as an Ising bond order, where ferromagnetic or antiferromagnetic correlations develop along one direction, but not the other.…”

Section: Introductionmentioning

confidence: 99%

“…SS magnetism can be captured within a J 1 -J 2 Heisenberg model on the square lattice, with an additional biquadratic coupling [3,4],…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Emergent Ising degrees of freedom above a double-stripe magnetic ground state

Zhang

Flint

2017

Double-stripe magnetism [ Q = ( π / 2 , π / 2 ) ] has been proposed as the magnetic ground state for both the iron-telluride and BaTi 2 Sb 2 O families of superconductors. Double-stripe order is captured within a J 1 − J 2 − J 3 Heisenberg model in the regime J 3 ≫ J 2 ≫ J 1 . Intriguingly, besides breaking spin-rotational symmetry, the ground-state manifold has three additional Ising degrees of freedom associated with bond ordering. Via their coupling to the lattice, they give rise to an orthorhombic distortion and to two nonuniform lattice distortions with wave vector ( π , π ) . Because the ground state is fourfold degenerate, modulo rotations in spin space, only two of these Ising bond order parameters are independent. Here, we introduce an effective field theory to treat all Ising order parameters, as well as magnetic order, and solve it within a large-N limit. All three transitions, corresponding to the condensations of two Ising bond order parameters and one magnetic order parameter are simultaneous and first order in three dimensions, but lower dimensionality, or equivalently weaker interlayer coupling, and weaker magnetoelastic coupling can split the three transitions, and in some cases allows for two separate Ising phase transitions above the magnetic one. Double-stripe magnetism [Q = (π/2,π/2)] has been proposed as the magnetic ground state for both the iron-telluride and BaTi 2 Sb 2 O families of superconductors. Double-stripe order is captured within a J 1 -J 2 -J 3 Heisenberg model in the regime J 3 J 2 J 1 . Intriguingly, besides breaking spin-rotational symmetry, the ground-state manifold has three additional Ising degrees of freedom associated with bond ordering. Via their coupling to the lattice, they give rise to an orthorhombic distortion and to two nonuniform lattice distortions with wave vector (π,π). Because the ground state is fourfold degenerate, modulo rotations in spin space, only two of these Ising bond order parameters are independent. Here, we introduce an effective field theory to treat all Ising order parameters, as well as magnetic order, and solve it within a large-N limit. All three transitions, corresponding to the condensations of two Ising bond order parameters and one magnetic order parameter are simultaneous and first order in three dimensions, but lower dimensionality, or equivalently weaker interlayer coupling, and weaker magnetoelastic coupling can split the three transitions, and in some cases allows for two separate Ising phase transitions above the magnetic one. Disciplines Condensed Matter Physics