Abstract
We study the quantum paraelectric-ferroelectric transition near a quantum critical point, emphasizing the role of temperature as a “finite-size effect” in time. The influence of temperature near quantum criticality may thus be likened to a temporal Casimir effect. The resulting finite-size scaling approach yields behavior of the paraelectric susceptibility and the scaling form , recovering results previously found by more technical methods. We use a Gaussian theory to illustrate how these temperature dependences emerge from a microscopic approach; we characterize the classical-quantum crossover in , and the resulting phase diagram is presented. We also show that coupling to an acoustic phonon at low temperatures is relevant and influences the transition line, possibly resulting in a reentrant quantum ferroelectric phase. Observable consequences of our approach for measurements on specific paraelectric materials at low temperatures are discussed.
3 More- Received 27 March 2008
DOI:https://doi.org/10.1103/PhysRevB.79.075101
©2009 American Physical Society