Research Fellows Directory
Dr Anoop Dhoot
University of Cambridge
Electronic charges induced at the surface of an electrical conductor by application of a voltage across a thin insulator (called the gate dielectric) are exploited in the field-effect transistor – the basis of current semiconductor technology. The concentration of charges induced at the surface of the semiconductor switches silicon from a low conductance state to a high conductance state. The charge density is typically limited by the dielectric strength of the insulator to about one charge for every hundred atoms at the surface. Although this low charge density is more than enough to switch the conductivity in semiconductors it has only a small effect on metallic materials.
It is now possible to use a different type of gate dielectric that contains many mobile ions that can be directed to move in response to an external voltage and used to induce very high charge densities in transistors – sufficiently high to change the conductivity of even metals.
My research work in Cambridge has focussed on the use of electrolyte dielectrics to gate manganites and cuprates – a class of materials that are known to show remarkable changes in conductivity when cooled down to low temperature. The electrolyte enables control of the temperature at which the very large changes in conductivity in such materials are found to occur. These results demonstrate the potential scope for ion gating to completely transform the properties at the surface of a wide range of materials that are inaccessible via traditional chemical preparation.
This project aims to develop the ion gating technique so that a broad range of new materials systems can be studied with the chance of a major discovery of unexpected exotic properties.
Interests and expertise (Subject groups)