For authors
Submission status

Archive (English)
      Volume 106
      Volume 105
      Volume 104
      Volume 103
      Volume 102
      Volume 101
      Volume 100
      Volume 99
      Volume 98
      Volume 97
      Volume 96
      Volume 95
      Volume 94
      Volume 93
VOLUME 103 | ISSUE 2 | PAGE 124
Long-range spin correlations in a honeycomb spin model with magnetic field
We consider spin-1/2 model on the honeycomb lattice (Ann. Phys. 321, 2 (2006)) in presence of weak magnetic field h_{\alpha }\ll J. Such a perturbation treated in the lowest nonvanishing order over hα leads (Phys. Rev. Lett. 106, 067203 (2011)) to a power-law decay of irreducible spin correlations \left\langle \left\langle s^{z}(t,r)s^{z}(0,0)\right\rangle \right\rangle
\propto h_{z}^{2}f(t,r), where f(t,r)\propto \lbrack \max (t,Jr)]^{-4}. In the present Letter we studied the effects of the next order of perturbation in hz and found an additional term of the order hz4 in the correlation function \left\langle\left\langle 
s^{z}(t,r)s^{z}(0,0)\right\rangle\right\rangle which scales as  h_z^4\cos\gamma/r^3 at Jt \ll r, where γ is the polar angle in the 2D plane. We demonstrate that such a contribution can be understood as a result of a perturbation of the effective Majorana Hamiltonian by weak imaginary vector potential A_x \propto i h_z^2.