A mean field theory for relaxor piezoelectrics and the piezoelectric transistor
- Event time: 1:00pm
- Event date: 5th May 2014
- Speaker: Flaviu Cipcigan (Formerly School of Physics & Astronomy, University of Edinburgh)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
IBM TJ Watson is working on a solution to the slowing down of Moore's law, in the form of a piezoelectric transistor (PET). In essence, a PET is a piezoresistive material sitting atop of a piezoelectric material, being clamped together by a material with a high tensile strength. Applying an electric field to a piezoelectric material causes it to expand, compressing the piezoresistive material. If the piezoresistor is chosen such that a small pressure change leads to a large resistive change and the piezoelectric such that a small voltage leads to a large pressure, the combination results in a fast, low voltage switch that can be used as a building block for logic gates and microchips.
A key component to a PET is a material with a large piezoelectric coefficient. A category of materials called relaxor piezoelectrics show such behaviour. They are solid mixtures of two perovskites, an example being lead magnesium niobate - lead titanate (PMN-PT). When the composition of PT is close to 33% (called the morphotropic phase boundary), these materials show a large piezoelectric response, dependant on their domain structure.
In this talk, I'll present ongoing efforts and open questions in theoretically understanding the behaviour of relaxor piezoelectrics such as PMN-PT
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..