We have studied the radio frequency dielectric response of a system consisting of separate polar water molecules periodically arranged in nanocages formed by the crystal lattice of the gemstone beryl. Below T = 20-30 K, quantum effects start to dominate the properties of the electric dipolar system as manifested by a crossover between the Curie-Weiss and the Barrett regimes in the temperature-dependent real dielectric permittivity ϵ′(T). When analyzing in detail the temperature evolution of the reciprocal permittivity (ϵ′)-1 down to T ≈ 0.3 K and comparing it with the data obtained for conventional quantum paraelectrics, like SrTiO3, KTaO3, we discovered clear signatures of a quantum-critical behavior of the interacting water molecular dipoles: Between T = 6 and 14 K, the reciprocal permittivity follows a quadratic temperature dependence and displays a shallow minimum below 3 K. This is the first observation of "dielectric fingerprints"of quantum-critical phenomena in a paraelectric system of coupled point electric dipoles.
Предметные области OECD FOS+WOS
- 1.03 ФИЗИЧЕСКИЕ НАУКИ И АСТРОНОМИЯ
- 2.11 ПРОЧИЕ ТЕХНОЛОГИИ
- 1.04 ХИМИЧЕСКИЕ НАУКИ
- 2.05 ТЕХНОЛОГИЯ МАТЕРИАЛОВ
- 2.03 МЕХАНИКА И МАШИНОСТРОЕНИЕ