Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 52: Focus Session: Realistic Dynamical Mean-Field Approaches
40mm to Correlated Quantum Materials

TT 52.5: Hauptvortrag

Mittwoch, 9. März 2016, 17:15–17:45, H20

Tin Foil at the Nanometer Scale - from Electronic Correlations to Topological Physics — •Ralph Claessen — Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, 97074 Würzburg, Germany

With respect to its electronic properties and compared to its semiconducting siblings C, Si, and Ge the group IV element tin (Sn) has always been a somewhat profane material. At ambient conditions Sn is a white-silverish metal (tetragonal β-Sn) and as tin foil has long been used for wrapping food (nowadays replaced by aluminum foil). At 13.2^∘ C a structural phase transition into the diamond-like α-phase occurs, known as "tin pest" which in former times posed a severe threat to church organ pipes in the winter time.

I will report on recent studies of (ultra)thin Sn films in which this elemental material displays highly interesting topological physics and correlation effects, otherwise seen only in materials of much higher structural or chemical complexity. This includes (1) the realization of compressively strained α-Sn as 3D topological insulator (TI), (2) our attempts to grow the Sn analogue of graphene, so-called stanene, which is predicted to be a 2D TI, and (3) the formation of triangular Sn lattices on semiconductor substrates, which display Mott-Hubbard physics and even magnetic instabilities despite the frustrated geometry.