Theory of Size Effects in Antiferroelectric Ceramic Nano Scale Films on Metal Substrates

摘要

This paper shows how a Landau thermodynamic theory can be utilized to study size effects in antiferroelectric thin films on metal substrates via reflectivity measurements in the terahertz region. A Landau free energy that includes a gradient term to describe the size effects is minimized. Landau Khalatnikov equations together with Maxwell's equations can then be solved to describe how the radiation interacts with the film. From this reflectivity curves can be calculated and related to experimental studies. The metal substrate is expected to influence the reflectivity curves compared to free standing films without substrates. This is significant since ceramic thin films are of technological importance, and films on metal substrates such as electrodes are relevant to applications such as memory devices. The main expectation is that terahertz wave measurements provide a sensitive probe of size effects and substrate influence.