Neutron scattering studies of spin dynamics in iron-based high-temperature superconductors

William Marsh Rice University, Houston TX

Investigators

Abstract

NON TECHNICAL ABSTRACT This award from the Condensed Matter Physics program of the Division of Materials Research supports a project addressing the fundamental physical processes that give rise to novel phenomena such as high-transition temperature superconductivity. Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. Understanding of superconductivity and related properties will not only enhance our knowledge of basic science, but also gives us the ability to design materials with novel and predictable properties. The investigators conduct neutron scattering experiments performed mostly at the high-flux isotope reactor (HFIR) and Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory. The project also utilizes other world-class facilities in the U.S. and Europe when similar capabilities are unavailable at HFIR and SNS. The impact of this research program will include the training of the next generation of neutron scattering experts and elucidating the nature of the special properties of the correlated electron materials. TECHNICAL ABSTRACT This award from the Condensed Matter Physics program of the Division of Materials Research supports an experimental program integrating neutron scattering experiments with laboratory-based materials efforts, aimed at the fundamental understanding of spin excitations and their relationship with superconductivity in iron-based high-transition-temperature (high-Tc) superconductors. The objective of the project is to explore and understand the microscopic origins of various phases in iron-based superconductors, specifically the iron arsenide superconductors BaFe2-xNixAs2, (B, K) Fe2A2, and BaFe2As2-xPx. The program has two components: initial materials characterization and neutron scattering. Single crystals of these materials are grown at the William Marsh Rice University where the initial characterization of will be performed. Neutron scattering, the core part of this research program, will be used to study the spin dynamical properties of these materials. Experiments will be performed at the High-Flux Isotope Reactor and the Spallation Neutron Source at Oak Ridge National Laboratory and the NIST Center for Neutron Research in Maryland. In addition, other world-class neutron scattering facilities in Europe will also be utilized when similar capabilities are unavailable in the US. The impact of this research program will include the training of the next generation of neutron scattering experts and elucidating the nature of the special properties of the correlated electron materials.