Dr Steven Hepplestone
The application of quantum theory to materials is fundamental to the world around us. Our research group works on the following areas:
The unique properties of both phase change materials as well as highly defective systems allow the possiblity of resistors whose properties change depending on their previous history.
We study both 2D and 1D structures, looking at the electronics and thermal properties and how various processes influence the devices performance.
The current focus here is on the potential of colossal permittivity materials. In joint colloboration with Deregallera, my research is focused on tackling the potential of these materials to form a new type of energy storage.
Thermoelectrics represent an intriguing possibility of turning heat directly into electricity. However, these materials are held back by being vast inefficiency. Using the latest techniques in theoretical physics, it is hoped that material can be designed at the nanoscale to produce a thermoelectric of high efficiency. In the past I have shown that the drop in thermal conductivity of multilayered nanofilms (known as superlattices) is due to the intermixing of atoms across the interface and the change in local bonds due to the lattice mismatch and strain. It is hoped that by controlling these mechanisms, an optimal thermoelectric can be found.
Given that interfaces govern the design of everything we build and design, it is often surprising to realise quite how poorly we understand their properties. In addition, these interfaces present opportunities to engineer and create properties one cannot see in normal solids, such superconductivity, ultrahigh resistances, unusual optical effects and more.
Crystal growth at the atomic level
Steven uses first principles calculations and empirical based approaches to help develop understand how one can influence and control the growth of crystalline materials and nanostructures at the atomic level. (more to come)
I have extensive experience in modelling nanoscale electronic components, be they transistors, capacitors or other components. If you are interested in developing these devices and are looking for advice and/or colloboration, please feel welcome to contact me.