Anna Böhmer, Division of Materials Science & Engineering, The Ames Laboratory, Iowa State University, Ames, IA, will present a Physics Department special seminar. Faculty candidate.

Seminar title: Electron-lattice coupling: access to interacting electronic phases

Abstract: The collective behavior of electrons in a solid can lead to emergent properties such as magnetism and superconductivity. In many classes of such quantum materials, the electronic degrees of freedom are intimately related to the structure. As a consequence, the properties of electronic phases and their relationships can be studied using structural degrees of freedom such as a change of the material’s volume or its resistance to structural deformations.
The recently discovered iron-based superconductors offer a uniquely rich field to investigate the interplay of electronic, magnetic and structural degrees of freedom. In particular, the antiferromagnetism in iron-based systems is closely linked to an orthorhombic distortion of the lattice, associated with a “nematic” electronic anisotropy. I will show how high-resolution measurements of the orthorhombic distortion and the elastic shear modulus elucidate the interplay of structure, magnetism and superconductivity. Combining these results with measurements of magnetic fluctuations further allows to study the relationship between nematicity and magnetism from a microscopic point of view. Finally, I will discuss a possible direct impact of nematicity on superconductivity, which might be probed using externally controlled deformations of the lattice.
 

Poster available.