MRI: Acquisition of an Ultrahigh-Resolution Photoelectron Spectrometer for Education and Research on Complex and Low-Dimensional Materials

University Of Tennessee Knoxville, Knoxville TN

Investigators

Abstract

Nearly all materials properties are determined by electrons close to the Fermi level, usually within 100 meV. In order to probe the behavior of electrons in this energy range, one needs to employ spectroscopy with ultrahigh resolution. This project entails the acquisition of an ultrahigh-resolution photoemission spectrometer of the Scienta type, which offers the best resolution that is currently achievable. This instrumentation will be used to investigate the electronic states in a wide variety of advanced electronic materials, including complex transition metal oxides, thin film nanostructures, organic superconductors, and atomic-wire arrays. Coupled with other spectroscopic methods, such as inelastic neutron scattering for probing spin and lattice excitations, and optical spectroscopy and Electron Energy Loss Spectroscopy for charge dynamics, it will enable researchers to unravel the highly complex entanglement of the spin, charge, and lattice degrees of freedom in these exotic materials. The new instrumentation will be based on campus, not at the synchrotron, so that students and faculty can have easy access and copious amounts of high quality photoemission time. The proposed science and new infrastructure will provide an excellent setting for the education and training of internationally competitive students and postdocs. Nearly all materials properties are determined by electrons close to the Fermi level, which represents the highest occupied energy level. Examples include electrical conductivity, magneto-resistance, superconductivity, and magnetism. In order to understand these important materials properties, one should probe the electrons near the Fermi level with ultrahigh resolution spectroscopy. From the late 1980s, Angular Resolved Photo-Emission Spectroscopy has been intensively applied to unravel the origins of superconductivity in high-temperature superconductors. In recent years the resolution of photoemission experiments has improved so much that electrons within a fraction of a milli-electronvolt around Fermi level can now be distinguished. Many of these potentially prize-winning studies have been published in highly prestigious journals because the ever increasing resolution unraveled novel properties that challenged the community and triggered new discovery. This project entails the acquisition of the world's best ultrahigh-resolution photoemission apparatus for the University of Tennessee. It will be used to study a wide variety of advanced electronic materials, including complex transition-metal oxides, thin film nanostructures, organic superconductors, and atom-wire arrays. A key aspect of the proposed research activities is that the powerful capabilities of this instrument will be combined with the local, complementary expertise and capabilities in neutron scattering and materials synthesis, thus providing researchers in East Tennessee with a competitive edge. The new instrumentation will be based on the Knoxville campus, not at a national synchrotron facility, so that students and faculty can have easy access and copious amounts of high quality photoemission time. The proposed science and infrastructure will also be accessible to the African American and Hispanic minority-student population at Florida International University and provide an excellent setting for the education and training of internationally competitive students and postdocs from diverse backgrounds.