Materials science

Argonne scientist receives American Physical Society awardNovember 23, 2015

The American Physical Society awarded chemist Mercouri Kanatzidis the 2016 James C. McGroddy prize for New Materials.

Superconducting Proximity Effect in Topological and Spin-orbit Materials

In recent years, there has been a renewed interest in the proximity effect due to its role in the realization of topological superconductivity. During this talk, we discuss several results that have been obtained in the field of proximity-induced superconductivity and relate the results to the search for Majorana fermions. First, we show that repulsive electron-electron interactions can induce a non-Majorana zero-energy bound state at the interface between a conventional superconductor and a normal metal and propose an experimental setup to observe such a state.

SU(4) Symmetry in Graphene Landau Levels: Break it or Not?

Landau levels in graphene have an approximate SU(4) symmetry in the spin and valley space. In this talk, I will present two contrasting symmetry patterns of quantum Hall states in graphene. At the charge neutrality point, the quantum Hall states spontaneously break the SU(4) symmetry, and the ground state is pinned down by the lattice-scale interactions and the Zeeman energy. I will describe an enlarged SO(5) symmetry identified in the valley-symmetry breaking interaction.

Employee Spotlight: Muge AcikNovember 17, 2015

Joseph Katz Fellow in Chemistry

Phase Diagram and Vortex Pinning of Iron-based Superconductors Tuned by Irradiation Induced Disorder

In my presentation I will discuss two applications of disorder controlled by energetic particle irradiation. First in the exploration of composition – temperature (x-T) phase diagram of canonical iron-based superconductor Ba(FeAs1-xPx)2. Upon isovalent substitution of As by P, temperature of spin density wave (SDW) transition decreases and dome of superconducting phase appears.

In the region of intersection of SDW transition line with superconducting dome several phenomena attract attention:

Argonne researchers win two R&D 100 AwardsNovember 16, 2015

Innovative technologies developed by researchers at Argonne and their partners earned two 2015 R&D 100 Awards.

Controlling Light at the Nanoscale via Novel Plasmonic Nanostructures

Plasmonics nanostructures are becoming remarkably important as tools towards manipulating photons at the nanoscale. They are poised to revolutionize a wide range of applications ranging from integrated optical circuits, photovoltaics, nano-antennas and biosensing.

Dislocations, Trijunctions and Grain Boundary Motion

Phase field crystal (PFC) models have been used to describe a wide range of phenomena from grain growth to solidification and dislocation motion in crystals. The method allows the atomic scale motion and defect formation to be determined on diffusive timescales. A short introduction to the PFC method will be presented. Using the PFC approach, the structure and dynamics of grain boundaries have been examined.