Surface Science and Nanostrutures

The research team is led by researchers from UCM belonging to the Surface Science and Nanostructures Group of the Faculty of Physics (Profs. A. Mascaraque, M.A. Gonzalez-Barrio and L. Perez), in collaboration with the Electronic Properties Group of Universidad Autonoma de Madrid (Profs. E.G. Michel, P. Segovia and C. Polop), belonging to Ifimac Research Center (www.ifimac.uam.es ). The group has a collaboration with Sandia National Laboratories-SNL (USA) and Laboratoire de Physique des Solides-LPS (France) on the topic of this project. A secondment at the LPS is foreseen. Our work focusses in the electronic and structural properties of surfaces and interfaces using state-of-the-art techniques like HR-ARPES, surface x-ray diffraction and scanning probe microscopies. Our work is complemented by research made in synchrotron radiation laboratories. We are currently running two projects on the topic of this proposal, entitled "Mott Physics for new applications in neuromorphic computing" (funded by Spanish Ministery of Science) and "Addressing the stress-related functional limitations of thin-film Li-ion components for energy-intensive applications" (M.era.Net project).

Energy consumption is a critical limitation for future devices. Semiconductor technologies have reached their intrinsic limitations and disruptive breakthroughs are required. Neuromorphic computing offers a new path towards devices with higher efficiency. Recent results of our collaborators in Sandia National Laboratories (USA) indicate that a device based upon a resistance switching mechanism using LixCoO2 offers a highly promising solution. LixCoO2 has been widely used as a charge storage material in batteries, but it may become soon critical for building a synaptic transistor. However, the physical mechanisms behind the operation of LixCoO2 are not yet understood. In particular, the electronic behavior of LixCoO2 is governed by a poorly understood metal-insulator transition that drives the compound from an insulating phase for LiCoO2 to a metal for the delithiated LixCoO2. <br />This project focuses on the electronic and structural properties of epitaxial thin films of LixCoO2, using photoelectron spectroscopy and microscopy, surface x-ray diffraction and scanning probe microscopies, both in our home laboratories in Madrid and in European synchrotron radiation laboratories. Epitaxial thin films of LixCoO2 grown ex-situ will be characterized,in order to understand their complex electronic behavior and the structural parameters determining it. The delithiation process, related to hole doping and relevant for operation, will be analyzed. Third, model systems suitable to understand the relevant physical processes in the metal-insulator transition will be studied. The goal of the project is to achieve a much better understanding of the physical processes governing the electronic behavior of LixCoO2, to improve its features and to find new materials with better characteristics.

<br /><br />Applicants should submit his/her Curriculum Vitae and a letter of motivation.<br />