Sotnikov A, Kuneš J
Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Praha 8, Czech Republic.
Sci Rep. 2016 Jul 27;6:30510. doi: 10.1038/srep30510.
Motivated by recent observation of magnetic field induced transition in LaCoO3 we study the effect of external field in systems close to instabilities towards spin-state ordering and exciton condensation. We show that, while in both cases the transition can be induced by an external field, temperature dependencies of the critical field have opposite slopes. Based on this result we argue that the experimental observations select the exciton condensation scenario. We show that such condensation is possible due to high mobility of the intermediate spin excitations. The estimated width of the corresponding dispersion is large enough to overrule the order of atomic multiplets and to make the intermediate spin excitation propagating with a specific wave vector the lowest excitation of the system.
受近期在LaCoO₃中观察到的磁场诱导转变的启发，我们研究了外场对接近自旋态有序和激子凝聚不稳定性的系统的影响。我们表明，虽然在这两种情况下转变都可以由外场诱导，但临界场的温度依赖性具有相反的斜率。基于这一结果，我们认为实验观察结果选择了激子凝聚的情形。我们表明，由于中间自旋激发的高迁移率，这种凝聚是可能的。估计的相应色散宽度足够大，足以推翻原子多重态的顺序，并使具有特定波矢传播的中间自旋激发成为系统的最低激发。
