Pyroelectricity of water ice.
Pyroelectricity of water ice.
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水冰的热电。
DOI：
10.1021/jp073870c
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
J. Cowin
中科院分区：
文献类型：
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作者：
Hanfu Wang;R. C. Bell;M. Iedema;G. Schenter;Kai Wu;J. Cowin
由于对称性，水冰通常被认为具有零热电性。然而，由于诱导部分偶极子排列，用离子偏置它会破坏对称性。这揭示了巨大的热释电。离子在温度高于 160 K 的情况下软着陆在 1 微米的水冰薄膜上。当冷却到 140-150 K 以下时，偶极子排列锁定。然后这些薄膜的功函数测量显示出 30 到 150 K 的高且可逆的热释电活动。对于 160 K 下沉积离子引起的约 10 V 的初始电压，在 150 K 以下观察到的偏差大约变化为 10 Vx(T/150K)2。这意味着水的热释电系数与许多商用热释电材料（例如锆钛酸铅（PZT））的热释电系数一样大。先前未报道过的水冰的热释电与使用 SPC 冰模型系统的谐波分析预测的结果相当一致。在结晶冰和致密非晶冰（无论是否氘化）中都可以观察到热释电。这意味着对于 0 到 150 K 之间的水冰（例如天体物理冰），温度变化会产生强电场（大约 10 MV/m），从而影响其化学性质、离子轨迹或结合。
Water ice usually is thought to have zero pyroelectricity by symmetry. However, biasing it with ions breaks the symmetry because of the induced partial dipole alignment. This unmasks a large pyroelectricity. Ions were soft-landed upon 1 mum films of water ice at temperatures greater than 160 K. When cooled below 140-150 K, the dipole alignment locks in. Work function measurements of these films then show high and reversible pyroelectric activity from 30 to 150 K. For an initial approximately 10 V induced by the deposited ions at 160 K, the observed bias below 150 K varies approximately as 10 Vx(T/150 K)2. This implies that water has pyroelectric coefficients as large as that of many commercial pyroelectrics, such as lead zirconate titanate (PZT). The pyroelectricity of water ice, not previously reported, is in reasonable agreement with that predicted using harmonic analysis of a model system of SPC ice. The pyroelectricity is observed in crystalline and compact amorphous ice, deuterated or not. This implies that for water ice between 0 and 150 K (such as astrophysical ices), temperature changes can induce strong electric fields (approximately 10 MV/m) that can influence their chemistry, ion trajectories, or binding.