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University of Cambridge > Department of Physics. Cavendish Laboratory > Theory of Condensed Matter > CoMePhS |
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Goals of the Group The Project The
CoMePhS project is a multicentered project to investigate and understand the physics
that could be used to develop electronic devices in a highly powerful and
novel way. How devices are made at the moment Electronic devices tend to be made by either
deposition on etching a layered material to exploit the properties of an
interface between dissimilar materials.
This manufacturing method requires very small scale manipulations to
the nature of the structure being used to create the device and as scales
reduce these manipulations become increasing difficult to do.
This picture shows the two common ways of device
manufacture. The top down approach
takes a multilayered device which has a mask in some way printed on it. This is exposed to an ion bean which
removes the film from the unmasked areas.
The mask is then removed, offen dissolved, and the device can then be
used, perhaps after repeating the process with chemically different layers. The bottom up approach requires a template to be
deposited on a substrate which attracts the electronically active
material. The process is again
repeated to make a device. These two
approaches have this in common, chemically different layers are built up on
each other. What we would like to develop However we would like to investigate a potentially
simpler method of manufacture that exploits materials that can naturally
adopt more than one electronic state.
These materials include manganites and other perovskites
If a layer of this material is deposited on the
substrate then instead of etching and depositing a chemically different
material to make the device we could use another method to change the phase
of only parts of the layer fabricating the device in many fewer steps. That the fabrication is hugely simplified is not
the only advantage here. In contrast
to the common methods where entire atoms are removed and replaced which
requires greater structural alterations to the device this way uses external manipulation to
create different electronic properties in the same material. The electronic junctions do not even have
to be at phase boundaries, perhaps as
the layer is deposited one may be able to exploit and control the electronic
properties of domain walls between the same phase. Indeed one might even go so far as to
develop a single phase with a periodic variation in electronic properties
which could be used in device manufacture. To make all this possible we need to understand
how we may control the electronic phase of the material we are going to use
in the device. It is this that is the
goal of the people in this group. These Pictures were taken from the paper Neil Mathur and Peter Littlewood, Nature Materials
3 (2004) 207 |
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