ARPES Studies of Complex Phases and Emergent Phenomena in Nonstoichiometric Transition Metal Oxides

Boston College, Chestnut Hill MA

Investigators

Abstract

Non-Technical In general metal oxides are good insulators. However, some transition metal oxides become unusual metals when extra electrons are added or removed through doping process. Many novel physical phenomena, such as high temperature superconductivity and colossal magnetoresistance, are discovered in those transition metal oxides. This experimental project is to study the electronic properties of several important transition metal oxides, using a modern technique of angle-resolved photoemission in which electrons are emitted from a material by absorbing ultraviolet (UV) light. The emitted electrons are then studied to gain information of their properties and configurations inside the material. The information of electronic structure of materials is crucial in understanding their physical and chemical properties that may have great application potentials. The success of this project will significantly advance our understanding of high temperature superconductivity in particular, and condensed matter physics in general. This project will also make a significant impact on education of students by introducing them to exciting new materials, cutting-edge techniques, and advanced physics. Technical This individual investigator award will support systematic angle-resolved photoelectron spectroscopy (ARPES) studies on complex phases and emergent phenomena in nonstoichiometric transition metal oxide (TMO) materials. It is known that many correlated TMO materials exhibit unusual physical phenomena, such as novel superconductivity and colossal magnetoresistance. The materials studied in this project include cuprates, ruthenates, and cobaltates, covering a wide space of two-dimensional TMO materials, from square to triangular lattice, and from 3d to 4d electron orbital. This project will focus on high-resolution ARPES measurements of Fermi surface evolution and low-energy excitations in various novel phases of these materials. A better understanding of electronic structure in these important TMO materials will significantly advance our knowledge of Mott physics, novel superconductivity, quantum criticality, and non-Fermi liquid physics. This project will also make an impact on the education of post-doc, graduate, undergraduate, and high school students by introducing them to exciting new materials, cutting-edge techniques, and fundamental condensed matter physics.