Is ice in ambient pressure really ordered under 72K? - Modern theoretical approach

我们用唯象模型，即KKY模型研究了冰的铁电性，它被认为是在72K常压下实现的。通过对包括Ice XI(铁电冰)在内的16种可能结构的研究，我们发现Ice XI并不是能量最低的。虽然这意味着当前模型的局限性，因为它与DFT分析相反，但我们认为这一结论是正确的。最大的原因是去极化效应。这使得冰XI的能量增加很大，而且无论它是稳定的还是不稳定的，它都变得相对不稳定。唯一的例外是小管(丝)结构，我们认为在实际材料中可能实现类似束状丝的结构。

We have studied the ferroelectricity of ice, which is believed to be realized under 72 K at ambient pressure by using a phenomenological mode, that is, KKY mode. By investigating totally 16 possible structures including Ice XI (ferroelectric ice), we have found that the Ice XI does not have the lowest energy. Although this means a limit of the present model because it is against the DFT analysis, we think that this conclusion is correct. The largest reason is the depolarization effect. which gives a large energy increase ti the Ice XI and it becomes relatively unstable whether it is stable or not without the depolarization effect. The only exception is the small tube (filament) structure, and we think that a structure like bundled filaments may be realized in the actual material.