18.06.18, 14:00 Uhr: Kolloquium - Prof. Dr. Joerg Schäfer:
'Novel Nanoscale Quantum Materials – From Design to Spectroscopy'


Am Montag, den 18.06.18, um 14:00 Uhr
spricht in einem außerordentlichen Kolloquium

Prof. Dr. Joerg Schäfer

University of Wuerzburg, Experimental Physics IV

zum Thema:

"Novel Nanoscale Quantum Materials – From Design to Spectroscopy"


Today, the quantum properties of a large range of materials have come into focus, because this reflects back onto the electronic and optical properties, and their application potential in terms of electron transport and computing. The underlying quantum physics becomes particularly apparent in nanoscale materials, where, e.g., the Coulomb interaction between atom starts to play a role, or when two-dimensional (2D) materials are realized that have specific spin transport properties. At the very heart of such studies is the epitaxial growth of materials with atomic scale control, which allows the realization of artificial material architectures that would otherwise not exist in nature. We will present an overview of several such designer materials. The high-resolution spectroscopic inspection by scanning tunneling microscopy and angle- and spin-resolved photoemission allows a full account of their electronic properties. By employing local spectroscopy with the tunneling tip, one can even detect the conduction channels of interest spatially resolved.

Key representatives include 2D electron systems grown on semiconductor wafers where one can control the degree of electron correlation, and the resulting conduction and spin properties. A second and very modern class of materials are topological insulators – which carry metallic conduction states at their surface, separated by spin character and inherently protected against defect scattering. These materials exist as bulk systems with large-area topological surface states, as photoemission data can illustrate nicely. With a perspective for applications, recent developments of 2D materials are particularly intriguing: when a graphene lattice is mimicked by very heavy atoms, specifically bismuth, one can generate a Bismuthene monolayer supported in an insulating substrate [F. Reis et al., Science 357, 287 (2017)]. It is a wide-gap quantum spin Hall insulator which exhibits protected conductive edge states at the flake boundaries – a candidate material for room temperature applications. The talk will present a perspective of the possibilities and challenges of such novel approaches for electronic quantum materials.

Gäste sind herzlich willkommen.



Leibniz-Institut für Kristallzüchtung

Raum 316, Geb. 19.31,

Max-Born-Str. 2

12489 Berlin-Adlershof


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