Ice XI Research Articles

Ferroelectricity of ice nanotube forests grown in three-dimensional graphene: the electric field effect.

Generating diverse ferroelectric ice nanotubes (NTs) efficiently has always been challenging, but matters in nanomaterial synthesis and processing technology. In the present work, we propose a method of growing ice NT forests in a single cooling process. A three-dimensional (3D) graphene structure was selected to behave as a representative container in which a batch of (5, 0) ice NTs was formed simultaneously under the cooling process from molecular dynamics simulation. Other similar 3D graphene structures but with different hole configurations, like uniform triangle or both triangle and pentagon, were also tested, revealing that ice NTs with different tube indices, i.e. both (3, 0) and (5, 0), could also be formed at the same time. Intriguingly, the orientations of the dipole moments of the water molecules of an ice NT formed were independent of each other, making the net ferroelectricity of the whole system weakened or even cancelled. An electric field could help change the orientation of the water molecules of the already obtained ice NTs and even twist the tube to be a spiral (5, 1) one if it was applied during the cooling process, such that the net ferroelectricity was greatly improved. The underlying physical mechanism of all phase transition phenomena, including the improvement of the ferroelectricity under an electric field, were explored in depth from the phase transition curves and structural point of view. The obtained results are of significant application value for improving the preparation efficiency of nano-ferroelectric materials, which are prosperous in nano-devices.

Discovering formation of ice 0 by low-frequency measurement data

In this work, low-frequency characteristics of wetted nanoporous silicate materials were measured, as well as the specimen’s own low-frequency electric fluctuations at the frequencies of 1…100 Hz. The measurements at low frequencies were conducted at different voltages of the probing signal. A capacity cell was used in making the measurements. In the experiments, at the temperatures below –25…–30 °C, non-linearity of the medium was discovered. The experiments on the study of the specimen’s own electric fluctuations at these temperatures revealed their essential increase. These temperatures are below the point of phase transition of supercooled water to recently discovered ferroelectric ice 0. Based on the measurements made, a conclusion was made regarding formation of this modification of ice in the nanosize pores of the wetted materials under study. Ice 0 is a ferroelectric; therefore, its formation from deeply supercooled water may have a significant impact on the electric parameters of wetted bodies at the temperatures below –23 °C. At the interface of such ice with another dielectric, a thin layer with practically metallic conductivity emerges. Such a layer influences not only the non-linear dependence of dielectric permittivity on the electric field but also increases attenuation of electromagnetic radiation in a medium.

Ferroelectric 2D ice under graphene confinement

We here report on the direct observation of ferroelectric properties of water ice in its 2D phase. Upon nanoelectromechanical confinement between two graphene layers, water forms a 2D ice phase at room temperature that exhibits a strong and permanent dipole which depends on the previously applied field, representing clear evidence for ferroelectric ordering. Characterization of this permanent polarization with respect to varying water partial pressure and temperature reveals the importance of forming a monolayer of 2D ice for ferroelectric ordering which agrees with ab-initio and molecular dynamics simulations conducted. The observed robust ferroelectric properties of 2D ice enable novel nanoelectromechanical devices that exhibit memristive properties. A unique bipolar mechanical switching behavior is observed where previous charging history controls the transition voltage between low-resistance and high-resistance state. This advance enables the realization of rugged, non-volatile, mechanical memory exhibiting switching ratios of 106, 4 bit storage capabilities and no degradation after 10,000 switching cycles.

Transmittance of Electromagnetic Radiation of the Visible Range by a Thin Film of Ice 0 Condensed on a Dielectric Substrate

The transmittance of electromagnetic radiation of the visible range through transparent dielectric samples with an ice nanolayer on their surface has been measured. Ice has been obtained by deposition of water vapor at a temperature of −170°C to 0°C. A decrease in the intensity of transmitted radiation at a wavelength of 0.52 μm by a factor of at least 2 depending on the material of the substrate and the temperature with a minimum near −23°C has been revealed. This effect is assumingly due to the formation of ferroelectric ice 0 and surface plasmons in a highly conducting thin layer at the ice 0–insulator interface.

ЛЁД 0 В ПРИРОДНОЙ СРЕДЕ. ЭКСПЕРИМЕНТАЛЬНЫЕ ДАННЫЕ И ПРЕДПОЛАГАЕМЫЕ ОБЛАСТИ ЕГО СУЩЕСТВОВАНИЯ

The paper presents the available experimental data on ice 0 and the assumed objects of the cryosphere in which it can exist. This ice is formed from supercooled volumetric water, and it precedes the formation of ices Ih or Ic, at temperatures below −23 °C. This crystalline modification has been recently predicted by computer simulations using methods of molecular dynamics. Ice 0 was then experimentally found by electromagnetic investigation of wetted nanoporous media. Interest in this modification of ice was aroused due to its special physical and chemical characteristics. A singularity of ice 0 is that it is a ferroelectric that has a high static dielectric constant. When ferroelectric ice 0 contacts other dielectrics at their boundaries a thin layer is formed due to the diffusion of electric charges, and its electrical conductivity is higher than that of the contacting media. High electrical conductivity in thin films allows investigating frozen dispersed media containing ice 0 using non-contact electromagnetic measurement methods. As this takes place, it becomes possible to register water freezing processes in objects existing at temperatures of −23 ÷ −100 C using microwave spectroscopy and remote sensing methods. It is assumed that ice 0 is involved in chemical transformations in different objects of the cryosphere – in the atmosphere, and vegetation and soil covers. Its formation in the pores of materials of man-made structures may exert influence on the life-time of mechanisms and structures at low temperatures due to increased electrocorrosion. Ice 0 is assumed to exist on cold planets and their moons. That is why studying the possibility of ice 0 appearing in different objects of the natural environment at negative temperatures is so important for understanding their properties and developing remote sensing methods.

Homogeneous nucleation of ferroelectric ice crystal driven by spontaneous dipolar ordering in supercooled TIP5P water.

Recently, it has been revealed that a supercooled liquid below the melting point has intrinsic structural heterogeneity due to local structural ordering as a manifestation of many-body correlations. The impact of such preordering on crystal nucleation has recently attracted considerable attention. In this work, by extensive molecular dynamics simulations of TIP5P water, we find a two-step homogeneous nucleation of a ferroelectric ice crystal: the first step is spontaneous dipolar ordering, i.e., paraelectric-to-ferroelectric transition, in a supercooled liquid state and the second step is the nucleation of the ferroelectric ice crystal selectively in the preordered regions. We reveal that in this system the dipole-dipole correlation grows rapidly with an increase in pressure, eventually leading to spontaneous dipolar ordering at a certain condition (e.g., at 2000 bars and 227 K). This result is obtained by simulations of TIP5P water with a simple cutoff of Coulomb interactions. By comparing this result with those of the particle-mesh Ewald and reaction field treatments of the Coulomb interactions, we find that the potential cutoff significantly enhances the dipole-dipole correlation, resulting in the fast ice nucleation to the ferroelectric cubic form. Despite the unrealistic enhancement of dipolar correlation in this model, this work provides an intriguing physical scenario of two-step crystal nucleation in polar molecules assisted by dipolar orientational ordering, which may be relevant to crystallizations, e.g., under an external electric field, on a charged surface, or under extreme conditions.

Analysis of Loss Factor of Supercooled Pore Water at Frequencies of 60–140 GHz

Loss factor of supercooled pore water is studied at frequencies of 60–140 GHz at temperatures of down to –70°C using silica gel. It is shown that, with disregard of the effect of monomolecular nonfreezing layer of bound water, the loss factor of pore water in the silicate material is determined by the Debye relaxation of water corresponding to the properties of bulk water, additional loss in a temperature interval centered at ‒45°C owing to the effect of the second critical point of water, and the surface conduction at the interface due to the formation of ferroelectric ice 0 provided that the freezing point of water in pores is lower than ‒23°C. The experimental results can be used in the problems of radiation transfer in aerosols and porous wetted finely dispersed media.

Origins of emergent high- Tc ferroelectric ordering in heteroepitaxial ice films: Sum-frequency generation vibrational spectroscopy of H2O and D2O ice films on Pt(111)

Using sum-frequency generation (SFG) spectroscopy, we have investigated ferroelectric orientational ordering of ${\mathrm{H}}_{2}\mathrm{O}$ and ${\mathrm{D}}_{2}\mathrm{O}$ crystalline-ice films grown on Pt(111) at 140 K. The $\mathrm{Im}{\ensuremath{\chi}}^{(2)}$ SFG spectrum of the hydrogen-bonded OH (OD) stretching band of ${\mathrm{H}}_{2}\mathrm{O}$ (${\mathrm{D}}_{2}\mathrm{O}$) ice film shows a couple of peaks whose signs are all negative, indicating net-H-down (net-D-down) ferroelectric orientational ordering of ${\mathrm{H}}_{2}\mathrm{O}$ (${\mathrm{D}}_{2}\mathrm{O}$) molecules with protons (deuterons) preferentially pointing toward the Pt substrate. The spectral features are analyzed in terms of the orientational ordering and OH (OD) vibrational excitons derived from intermolecular couplings. The quantitative analysis of the SFG peak intensity demonstrates the layer-dependent strong ferroelectric orientational ordering. Temperature dependence of the SFG intensity indicates that the ferroelectric orientational ordering decays via second-order type ferroelectric-paraelectric transition at critical temperatures of ${T}_{c}=163$ and 167 K for ${\mathrm{H}}_{2}\mathrm{O}$ (50 bilayers thickness) and ${\mathrm{D}}_{2}\mathrm{O}$ (64 bilayers thickness) ice films, respectively, which are more than twice as large as that of ferroelectric bulk ice XI (${T}_{c}\ensuremath{\sim}72\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ for ${\mathrm{H}}_{2}\mathrm{O}, {T}_{c}\ensuremath{\sim}76\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ for ${\mathrm{D}}_{2}\mathrm{O}$). The isotope shift of ${T}_{c}$ for the high-${T}_{c}$ ferroelectric ice films on Pt(111) is only about 4 K, which is in stark contrast to a large isotope shift of ${T}_{c}$, approximately several tens of Kelvin, of typical high-${T}_{c}$ hydrogen-bonded ferroelectrics. The interadsorbate and adsorbate-substrate interactions at the ice/Pt interface and nuclear quantum effects in the hydrogen-bond network of ice film are responsible for the observed thermal stability of ferroelectric orientational ordering and its isotope effect.

Alternating current breakdown voltage of ice electret

Ice has low environmental impact. Our research objectives are to study the availability of ice as a dielectric insulating material at cryogenic temperatures. We focus on ferroelectric ice (iceXI) at cryogenic temperatures. The properties of iceXI, including its formation, are not clear. We attempted to obtain the polarized ice that was similar to iceXI under the applied voltage and cooling to 77 K. The polarized ice have a wide range of engineering applications as electronic materials at cryogenic temperatures. This polarized ice is called ice electret. The structural difference between ice electret and normal ice is only the positions of protons. The effects of the proton arrangement on the breakdown voltage of ice electret were shown because electrical properties are influenced by the structure of ice. We observed an alternating current (ac) breakdown voltage of ice electret and normal ice at 77 K. The mean and minimum ac breakdown voltage values of ice electret were higher than those of normal ice. We considered that the electrically weak part of the normal ice was improved by applied a direct electric field.

Signatures of the appearance of ice 0 in wetted nanoporous media at electromagnetic measurements

Ice 0 that is a new modification of crystalline ice, which can be formed only from supercooled water, is sought. To this end, the electric parameters of wetted nanoporous silicates SBA-15 and silica gel (Acros) for obtaining deeply supercooled water in pores are studied. Three electrical parameters of a medium are measured: the reflection coefficient of microwave radiation from the interface between the medium and air in a waveguide at a frequency of 12.4 GHz and the transmittance of radiation at a frequency of 94 GHz, the tangent of the dielectric loss angle at frequencies from 10 Hz to 100 kHz, and the characteristic electrical fluctuations in the frequency band of 1–100 Hz. Studies are performed at cyclic cooling and heating of the samples in the temperature range from + 20 °C to -150 °C. Sharp changes in all three parameters of the wetted silicates are revealed near the temperature range from -20 °C to - 24 °C. These changes can be attributed to the formation or destruction of ferroelectric ice 0.

極低温での氷エレクトレットの脱分極電流特性

We have been studying the characteristics of ice as a dielectric or electrical insulation material at cryogenic temperature. IceXI, ferroelectric ice, exists at cryogenic temperature. It is very difficult to make iceXI. We applied direct-currentvoltage to ordinary ice at 253 K and cooled it to 77 K to obtain a polarized ice similar to iceXI. In this procedure, the protons move towards the cathode side under an electric field. The protons were stopped on the cathode side by cooling to 77 K, resulting in ice polarization. This polarized ice is called “ice electret”. We have previously reported the amount of electrical charge calculated from an integral of the ice electret depolarization current observed. The amount of charge increased as voltage and application time increased. In this paper, the effect of voltage, application time and temperature on depolarization current properties of the ice electret is reported. The depolarization current of the ice electret was examined in detail. Two peaks were observed in the depolarization current. One peak appeared around 270 K. But this peak did not occur in the specimen with a voltage of 140 K applied. The other peak was observed around 130 K in any specimen. The electrical charge calculated from this 130 K peak increased only when a voltage was applied, and did not increase as time and temperature increased when voltage was applied.

Поиски сегнетоэлектрических льдов в пористых средах в земных условиях

Поиски сегнетоэлектрических льдов в пористых средах в земных условиях

The search for ferroelectric ice in porous media on the Earth.

The search for ferroelectric ice in porous media on the Earth.

Raman and IR Spectra of Ice Ih and Ice XI with an Assessment of DFT Methods.

IR and Raman spectroscopic technology can be directly used to identify the occurrence of ferroelectric ice XI in laboratory or extraterrestrial settings. The performance of 16 different DFT methods applied on the ice Ih, VIII, IX, and XI crystal phases is evaluated. Based on a selected DFT computational scheme, the IR and Raman spectra of ice Ih and XI are derived and compared. When the spectra, both IR and Raman, of ice Ih and ice XI are compared, the librational vibrations are found to be the most affected by the proton ordering. The spectroscopic fingerprint of ice XI can be used to distinguish ferroelectric ice XI from ice Ih in the universe. Furthermore, the existence of only one kind of H-bond in ice Ih is demonstrated from the overlapping subspectra for different types of H-bonded pair configurations in 16 isomers of ice Ih, which provides an illustration to the historic debate on whether one or two kinds of H-bonds existed in ice.

氷エレクトレットの作製と電荷量

Ferroelectric ice, ice XI, existing at the cryogenic temperature of 1 atm is a very interesting material because of its high electrical stability at low temperature and its low environmental impact. However, the ice XI formation process is very difficult. The dielectric properties of ice are governed by the behavior of the hydrogen ions, protons. Protons in ice can hop along lattice defects at a relatively high temperature, e.g., 253 K. At a cryogenic temperature such as 77 K, proton movement in ice is difficult. To obtain polarized ice, we applied DC voltage to normal ice, ice Ih, at 253 K and cool it down to 77 K with voltage application. In this process, protons in ice hop to the cathode side at 253 K and stop moving at 77 K, therefore polarization fixed there. The polarized ice is called "ice electret." The electrical properties and structure of ice electret have not yet been clarified. We produced ice electret using the aforementioned method and observed its depolarization current. We changed the application time and magnitude of voltage in during the formation process and measured the charged stored in the ice electrets produced. The results show that the stored charge in ice electret increases with application time and amplitude of voltage.

Ice XI: Not That Ferroelectric

Ice XI, the proton-ordered phase of ordinary ice, features aligned water dipoles. It can be synthesized under laboratory conditions at T ∼ 72 K. Recently, speculations on ice XI in the solar system and the role of its possibly large electric fields in planetary formation have appeared in the literature. We have studied the energetics of ice Ih proton configurations using finite ice slabs and periodic supercell density functional theory (DFT) calculations, while properly taking into account the depolarization field associated with increasing proton order. The depolarization field, not taken into account in previous DFT calculations, dominates the energetics, making the existence of ferroelectric ice unlikely. A single order parameter is shown to describe both the surface dangling-bond configuration and the overall polarization state of the slab. According to our calculations, doping ice with alkali hydroxides or placing it in contact with a metal surface stabilizes a net alignment of water molecule dipoles...

Spectroscopic signature for ferroelectric ice

Various forms of ice exist within our galaxy. Particularly intriguing type of ice – ‘ferroelectric ice’ was discovered experimentally and is stable in temperatures below 72K. This form of ice can generate enormous electric fields and can play an important role in planetary formation. In this letter we present Car–Parrinello simulation of infrared spectra of ferroelectric ice and compare them with spectra of hexagonal ice. Librational region of the spectra can be treated as spectroscopic signature of ice XI and can be of help to identify ferroelectric ice in the Universe.

Investigation of ferroelectric phase transitions of water in nanoporous silicates in simultaneous electrical noise and calorimetric measurements

The phase transitions of water in the nanoporous silicate materials SBA-15 and MCM-41 with an ordered system of cylindrical pores have been investigated. Measurements of low-frequency electrical noises (Barkhausen noises) in the frequency range of 1–100 Hz have been performed simultaneously with relative calorimetric measurements. It has been found that the voltage of electrical fluctuations increases approximately 100 times in the temperature range from −30 to −50°C, which is associated with the first-order and second-order ferroelectric phase transitions. It has been assumed that the ferroelectric ice XI can be formed in capillary pores of the materials under investigations.

First-principles study of spontaneous polarisation and water dipole moment in ferroelectric ice XI

Using density functional calculations, spontaneous polarisation of proton-ordered ferroelectric ice XI phase is calculated for the first time. Spontaneous polarisation along the c-axis of orthorhombic structure is calculated to be , which corresponds to water dipole moment 3.3 D. We have performed systematic calculation of the water dipole moment in proton-ordered ice without ambiguity.

Single-Domain Ferroelectric Water and its Concerted Diffusion in Nanotubes

The term ‘ferroelectric water’ has so far stood for ‘ferroelectric ice.’ In molecular dynamics simulations, we find that, counter to intuition, single-domain ferroelectric water is possible inside carbon nanotubes open to a liquid water reservoir. Though this water is tube-shaped, it is strikingly different in structure and dynamics from ‘ice nanotubes.’ A series of step-wise changes in net polarization of water and mobile/immobile water transitions are observed to occur spontaneously. This study not only improves our general knowledge of water, but is also suggestive of potential multifunctional capabilities of simple hydrophobic nanotubes for future applications.