A Fluctuating State in the Framework Compounds (Ba,Sr)Al2O4
A Fluctuating State in the Framework Compounds (Ba,Sr)Al2O4
复制标题
骨架化合物(Ba,Sr)Al2O4中的涨落态
作者：
Y. Ishii;H. Tsukasaki;E. Tanaka;S. Mori
六方晶系Ba 1 − xSrxAl 2 O 4与角共享AlO 4四面体网络的结构波动在不同温度下使用透射电子显微镜实验进行了表征。当x ≤ 0.05时，q ~（1/2，1/2，0）的软模和等效波矢在相变温度（TC）处凝聚，形成体积为2a × 2b × c的超结构。然而，TC在很大程度上被Sr取代抑制，并且当x ≥ 0.1时消失。此外，q ~（1/2，1/2，0）软模随温度的降低而偏离公度值，并在~200 K以下的纳米尺度范围内存在。这些结果有力地表明存在一个新的量子临界诱导的软模式。在高达800 K的高温区，观察到两种不同的软模作为蜂窝型漫散射。这种内在的结构不稳定性是骨架化合物的独特特征，并且是这种异常波动状态的原因。
The structural fluctuation in hexagonal Ba1−xSrxAl2O4 with a corner-sharing AlO4 tetrahedral network was characterized at various temperatures using transmission electron microscopy experiments. For x ≤ 0.05, soft modes of q ~ (1/2, 1/2, 0) and equivalent wave vectors condense at a transition temperature (TC) and form a superstructure with a cell volume of 2a × 2b × c. However, TC is largely suppressed by Sr-substitution and disappears for x ≥ 0.1. Furthermore, the q ~ (1/2, 1/2, 0) soft mode deviates from the commensurate value as temperature decreases and survives in nanoscaled regions below ~200 K. These results strongly suggest the presence of a new quantum criticality induced by the soft mode. Two distinct soft modes were observed as honeycomb-type diffuse scatterings in the high-temperature region up to 800 K. This intrinsic structural instability is a unique characteristic of the framework compound and is responsible for this unusually fluctuating state.
影响因子：
19.6
作者：
Joe, Y. I.;Chen, X. M.;Abbamonte, P.
通讯作者：
Abbamonte, P.