Complex pressure-temperature structural phase diagram of the honeycomb iridate Cu2IrO3
Complex pressure-temperature structural phase diagram of the honeycomb iridate Cu2IrO3
复制标题
蜂窝状铱酸盐 Cu2IrO3 的复杂压力-温度结构相图
DOI：
10.1103/physrevb.104.014102
复制
发表时间：
2021
影响因子：
3.7
通讯作者：
Kolmogorov, A. N.
中科院分区：
文献类型：
--
作者：
Fabbris, G.;Thorn, A.;Bi, W.;Abramchuk, M.;Bahrami, F.;Kim, J. H.;Shinmei, T.;Irifune, T.;Tafti, F.;Kolmogorov, A. N.
是最新的层状蜂窝状铱酸盐之一，也是基塔耶夫量子自旋液态的有希望的候选物。在这里，我们通过粉末x射线衍射和x射线吸收精细结构测量相结合，以及初始演化结构搜索来研究其结构的压力和温度依赖性。在环境压力下，我们用一个相关但明显更稳定的结构修改了先前提出的解决方案。低于8gpa的压力在常温和低温下都能驱动Ir-Ir二聚体的形成，类似于。在较高的压力下，结构的演变很大程度上取决于温度。在室温下，在15gpa左右观察到Ir蜂窝面间距离的大量不连续减小，这可能是由O-Cu-O哑铃键的崩溃驱动的。在15 K时，超过20 GPa的压力首先导致中间相，其面间距离不断减小，然后在30 GPa时发生另一个相变。然而，在室温和低温下，在40gpa附近得到的结构是不一样的。值得注意的是，面间距的减小导致层错在室温下明显愈合，而在15k时则没有。讨论了电子结构随压力变化的可能意义。
is among the newest layered honeycomb iridates and a promising candidate to harbor a Kitaev quantum spin liquid state. Here, we investigate the pressure and temperature dependence of its structure through a combination of powder x-ray diffraction and x-ray absorption fine structure measurements, as well asab initioevolutionary structure search. At ambient pressure, we revise the previously proposedsolution with a related but notably more stablestructure. Pressures below 8 GPa drive the formation of Ir-Ir dimers at both ambient and low temperatures, similar to the case of. At higher pressures, the structural evolution dramatically depends on temperature. A large discontinuous reduction of the Ir honeycomb interplanar distance is observed around 15 GPa at room temperature, likely driven by a collapse of the O-Cu-O dumbbell bonds. At 15 K, pressures beyond 20 GPa first lead to an intermediate phase featuring a continuous reduction of the interplanar distance, which then collapses at 30 GPa across yet another phase transition. However, the resulting structure around 40 GPa is not the same at room and low temperatures. Remarkably, the reduction in interplanar distance leads to an apparent healing of the stacking faults at room temperature, but not at 15 K. Possible implications on the evolution of electronic structure ofwith pressure are discussed.