Berlin 2018 – scientific programme

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DS: Fachverband Dünne Schichten

DS 37: 2D Materials: Session III (joint session DS/CPP/HL)

DS 37.1: Invited Talk

Friday, March 16, 2018, 09:30–10:00, H 2032

Tunable Electronic Structures, Magnetism, and Axis-Dependent Conduction Polarity in Ge and Sn-based 2D Materials — •Joshua Goldberger — The Ohio State University, Columbus, OH USA

Here, we will discuss recent developments in the synthesis, properties, and applications of two classes of Ge- and Sn-based 2D materials; the ligand-functionalized Ge/Sn graphane analogues, and the exfoliatable van der Waals Zintl phases. First, the Ge/Sn graphane analogues have generated much excitement as their electronic structures are predicted to range from trivial insulators, to semiconductors with tunable gaps, to semimetallic, to topological insulators, depending on the substrate, chemical functionalization and strain. Through the synthesis and characterization of a large family of ligand-functionalized germananes, we will show how the electronic structure can be manipulated via surface chemistry. Second, we will highlight a new family of chemically and thermally robust exfoliatable 2D materials having a stoichiometry of ASn2Pn2, where A is a cation, and Pn is a pnictogen. This class of materials can be designed to exhibit a broad range of phenomena including the topological insulating compound, SrSn2As2, as well as the magnetic compound, EuSn2As2. Also, we will show that NaSn2As2 simultaneously exhibits opposite sign conduction polarities along its in-plane and cross-plane axes. Using a variety of advanced transport measurements we establish the band structure origins of this behavior. Together, these materials show how the inherent anisotropy in 2D materials can be rationally tailored to give rise to new phenomena.