Electron Spectroscopy Group

Welcome to the home page for the Electron Spectroscopy Group, a member of the Condensed Matter Physics and Materials Science Department at Brookhaven National Laboratory on Long Island, New York.

The focus of the electron spectroscopy program is the exploration of the electronic structure and electrodynamics of topological insulators and strongly correlated electron systems, with particular attention to emergent phenomena, such as superconductivity and magnetism, using angle-resolved photoemission (ARPES) and optical spectroscopy. A central goal of the program is to discover the mechanism of superconductivity in the high-temperature superconductors and to better understand the role of spin- and charge-orders that shape the phase diagrams of these materials, particularly in the low-doping regimes. These studies will be extended to heavier transition-metal oxides and other low-dimensional materials in which both the correlation and spin-orbit coupling energies are comparable to band energies. In these materials, the effects of strong spin-orbit coupling and correlations could lead to a myriad of different phases and phenomena. In addition, interaction of topological materials with materials displaying other ground states, in particular with magnetism and superconductivity, will be studied, as the proximity of these two distinct types of matter is expected to produce exotic new phenomena, some of which could be applied in devices. In order to carry out these studies instrumentation will be developed for both ARPES and optical reflectance studies featuring lab-based light sources as well as instruments for future beamlines at NSLS II.

A brief survey of current research topics include:

• High-Tc cuprates and iron-based superconductors
• Topological insulators
• Charge ("stripe") order in the nickelates
• Correlated electron systems (intermetallics, etc.)
• Density-functional theory ab-initio calculations of electronic band structure and lattice dynamics of perovskites

Our experiments are typically performed on single crystal samples, many of which are grown and characterized at Brookhaven.