Magnetic anisotropy from linear defect structures in correlated electron systems

M Pal and L Bettmann and A Kreisel and PJ Hirschfeld, PHYSICAL REVIEW B, 103, 245132 (2021).

DOI: 10.1103/PhysRevB.103.245132

Correlated electron systems, particularly iron-based superconductors, are extremely sensitive to strain, which inevitably occurs in the crystal growth process. Built-in strain of this type has been proposed as a possible explanation for experiments where nematic order has been observed at high temperatures corresponding to the nominally tetragonal phase of iron-based superconductors. Strain is assumed to produce linear defect structures, e.g., dislocations, which are quite similar to O vacancy chainlets in the underdoped cuprate superconductor YBCO. Here we investigate a simple microscopic model of dislocations in the presence of electronic correlations which create defect states that can drive magnetic anisotropy of this kind, if spin-orbit interaction is present. We estimate the contribution of these dislocations to magnetic anisotropy as detected by current torque magnetometry experiments in both cuprates and Fe-based systems.

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