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We study vacancies in non-collinearly ordered 2D quantum Heisenberg antiferromagnets.
Since in a collinearly ordered system vacancies can be seen as point scatterers, the situation is more difficult in the non-collinear case.
Here, a distortion appears which surrounds the vacancy.
We perform a classical Monte Carlo simulation which determines the structure of such a distortion in the triangular lattice, with and without magnetic field. The distortion declines as r-3 and shows an interesting local structure. We perform a linear spin-wave calculation on top of the distorted classical ground state and derive quantum corrections to the magnetization and spin-correlation functions. In particular, we calculate the impurity contribution to the uniform susceptibility both at zero and finite temperatures. |
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