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arXiv · 0811.1294

Theory of Magnetic Order in $ Fe_{1+y}Te_{1-x}Se_x$

Chen Fang·B. Andrei Bernevig·Jiangping Hu
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Abstract

We develop a local spin model to explain the rich magnetic structures in the iron-based superconductors $Fe_{1+y}Te_{1-x}Se_x$. We show that our model exhibits both commensurate antiferromagnetic and incommensurate magnetic order along the crystal a-axis. The transition from the commensurate to the incommensurate phase is induced when the concentration of excess $Fe$ atoms is larger than a critical value. Experimentally measurable spin-wave features are calculated, and the mean-field phase diagram of the model is obtained. Our model also suggests the existence of a large quantum critical region due to strong spin frustration upon increasing $Se$ concentration.

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Chen Fang, B. Andrei Bernevig, Jiangping Hu. 2008-11-08. Theory of Magnetic Order in $ Fe_{1+y}Te_{1-x}Se_x$. https://doi.org/10.1209/0295-5075%2F86%2F67005

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