PNNL

Abstract

Water ice usually is though to have zero pyroelectricity by symmetry. But biasing it with ions breaks the symmetry because of the induced partially dipole-aligned. This unmasks a large pyroelectricity. Ions were soft-landed upon 1 micron films of water ice at = 160K. When cooled below 140 to 150 K this locks-in the dipole-alignment. Workfunction measurements of these films then show high and reversible pyroelectric activity from 30 to 150K. For an initial ~10V induced by the deposited ions, the at 160K, the observed bias below 150K varies approximately as 10V*(T/150K)2 This implies 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 via a monte carlo simulation of TIP4P ice. This is observed in crystalline and compact amorphous ice, deuterated or not. This implies that for water ice between 0 and 150K (such as astrophysical ices), temperature changes can induce strong electric fields (~10,000,000 V/m) that can influence their chemistry and trajectories or binding.