Novel and conductive properties of new ceramic material

Materials World magazine
1 Jun 2006

Researchers at the London Centre for Nanotechnology (LCN), UK, have gained a better understanding of the properties of an unusual ceramic. The material, which is an oxide of manganese, has been found to conduct electricity only in certain directions, offering the potential for new designs for electronic devices.

Made by an international team led by University College London, the breakthrough offers the possibility of constructing three-dimensional structures - conventional devices tend to use two-dimensional integrated circuits. The UK team has been working with researchers from the Swiss Federal Institute of Technology (ETH), Zurich, the University of Tokyo, Japan, and Lucent Technologies, USA.

Professor Gabriel Aeppli, Director of LCN and co-author of the study, says, 'There is an issue of how you deal with leakage between layers when you pack circuits into three dimensions. Our work with the Tokyo-Lucent groups shows that you can have many ordinary layers with little or no leakage between them'.

'This is because we're not dealing with ordinary electrons, but with larger objects, consisting of electrons bound to magnetic and other disturbances of the atomic fabric of the material, which can't travel across the barriers between layers'.

Using a scanning tunneling microscope, Dr Henrik Rønnow (ETH) and Dr Christoph Renner (LCN and UCL) swept a metallic tip over the surface of the ceramic, taking data with a spatial resolution of less than the diameter of an atom. The results suggest this ceramic behaves like a conductor in lines parallel to the surface, but like an insulator in directions perpendicular to it. A possible explanation for this behaviour might lie with polarons - a combination of an electron and a lattice distortion.