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Small-scale phase separation in doped anisotropic antiferromagnets

M. Yu. Kagan·K. I. Kugel·A. L. Rakhmanov·K. S. Pazhitnykh
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Abstract

We analyze the possibility of the nanoscale phase separation manifesting itself in the formation of ferromagnetic (FM) polarons (FM droplets) in the general situation of doped anisotropic three- and two-dimensional antiferromagnets. In these cases, we calculate the shape of the most energetically favorable droplets. We show that the binding energy and the volume of a FM droplet in the three-dimensional (3D) case depend only upon two universal parameters $\bar{J} =(J_x + J_y + J_z)S^2$ and $t_{eff} =(t_xt_yt_z)^{1/3}$, where $\bar{J}$ and $t_{eff}$ are effective antiferromagnetic (AFM) exchange and hopping integrals, respectively. In the two-dimensional (2D) case, these parameters have the form $\bar{J} =(J_x + J_y)S^2$ and $t_{eff} =(t_xt_y)^{1/2}$. The most favorable shape of a ferromagnetic droplet corresponds to an ellipse in the 2D case and to an ellipsoid in the 3D case.

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M. Yu. Kagan, K. I. Kugel, A. L. Rakhmanov, K. S. Pazhitnykh. 2006-07-25. Small-scale phase separation in doped anisotropic antiferromagnets. https://doi.org/10.1088/0953-8984%2F18%2F48%2F018

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