Structural Study of CuNCN and Its Theoretical Implications: A Case of a Resonating-Valence-Bond State?статья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 19 июля 2013 г.
Аннотация:We present the results of a high-resolution low-temperature synchrotron structural study of the nitrogen-containing analogue of cupric oxide, copper carbodiimide (CuNCN). The material clearly manifests a surprising nonmonotonous behavior of the a lattice parameter as a function of the temperature: its decrease with decreasing temperature turns to a distinguishable increase below 100 K. The onset temperature of this anomaly nearly coincides with that of the onset of the activation temperature dependence, as seen from the magnetic susceptibility, which has been tentatively attributed to the formation of a gapped 2D spin-liquid (resonating-valence-bond) state. In accord with this assumption, we develop a theory relating the temperature behavior of the spin susceptibility to that of the lattice parameter, which semiquantitatively agrees with the observed behavior.