From photoconductivity and transmission spectra the dependence of the forbidden band width ϵg of tellurium on pressure (up to 10 kbar) at 300, 77, and 1.5 to 4.2 K is determined. This dependence is shown to be nonlinear, well described by the exponential relation ϵg(P) = ϵg0, e ‐ ϵaP where the α‐values differ not more than 15% at a temperature variation from 1.5 to 300 K.

Intermolecular hydrogen bonds impede long-range (anti-)ferroelectric order of water. We confine H 2 O molecules in nanosized cages formed by ions of a dielectric crystal. Arranging them in channels at a distance of~5 Å with an interchannel separation of~10 Å prevents the formation of hydrogen networks while electric dipole-dipole interactions remain effective. Here, we present measurements of the temperature-dependent dielectric permittivity, pyrocurrent, electric polarization and specific heat that indicate an order-disorder ferroelectric phase transition at T 0 ≈ 3 K in the water dipolar lattice. Ab initio molecular dynamics and classical Monte Carlo simulations reveal that at low temperatures the water molecules form ferroelectric domains in the ab-plane that order antiferroelectrically along the channel direction. This way we achieve the long-standing goal of arranging water molecules in polar order. This is not only of high relevance in various natural systems but might open an avenue towards future applications in biocompatible nanoelectronics.