Order from Disorder: Nonmagnetic Impurities in the Spin-Gap Phase of the Cuprates

This is the authors' abstract. We don't add key points for this paper.

We solve the problem of N nonmagnetic impurities in the staggered flux phase of the Heisenberg model which we assume to be a good mean-field approximation for the spin-gap phase of the cuprates. The density of states is evaluated exactly in the unitary scattering limit and is proportional to 1/ωln²(|ω|/D), in analogy with the 1D case of doped spin-Peierls and two-leg ladder compounds. We argue that the system exhibits a quasi-long-range order at T0ex0ex=0ex0ex0 with instantaneous spin-spin correlations decreasing as nᵢ/ln²(nᵢRᵢⱼ) for large distances Rᵢⱼ and we predict enhanced low energy fluctuations in neutron scattering.