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Extended Moment Formation and Second Neighbor Coupling in Li$_2$CuO$_2$

Ruben Weht·W. E. Pickett
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Abstract

Comprised of ferromagnetic edge-sharing CuO$_2$ chains that order in antialigned fashion at T$_N$=9 K, Li$_2$CuO$_2$ is found from local spin density calculations to display several surprising characteristics: (1) the ordered moment/f.u. of 0.92 $μ_B$ is the largest for any low dimensional cuprate system, in agreement with experiment, (2) 40% of this moment lies on the neighboring O ions, making it the largest oxygen moment yet reported, and (3) the second neighbors couplings are larger than nearest neighbors couplings. All of these phenomena arise naturally due to a well defined effective $d_{yz}$ type orbital that includes very strong O $p_σ$ character. We interpret the large moment as surviving reduction by quantum fluctuations due to extension caused by the $d-p$ hybridization.

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Ruben Weht, W. E. Pickett. 1998-05-22. Extended Moment Formation and Second Neighbor Coupling in Li$_2$CuO$_2$. https://doi.org/10.1103/physrevlett.81.2502

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