Talks for the CRC Members in 2020

 
 
 
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Presentation Abstract:
 
Metallic two-dimensional (2D) transition metal chalcogenides and halides, held together by van der Waals forces, exhibit a compellingly wide range of exotic and potentially useful properties such as charge density waves, topological insulator edges, and superconductivity. Importantly, one can also realize these properties by stabilizing new 2D allotropes of traditionally 3D superconductors and magnets. Our key advance toward the creation of single-crystal, environmentally stable 2D metals is Confinement Heteroepitaxy (CHet). In this talk, I will discuss how we are able to create these atomically thin metals, and the unique properties that result from doing so.
 
Please note that the details are in EST and this meeting will take place at 4:00 pm CET on June 26, 2020 for Kiel University attendees.
 
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Presentation Abstract:
 
 
Maturing the thin film growth of emerging materials to reduce the level of defects is a mandatory prerequisite to study their intrinsic physics and to innovate new device functionalities. Two classes of material systems, namely transition metal oxide and transition metal chalcogenide compounds offer a particularly rich palette of properties, hosting a wide range of different electronic ground states with sizeable coupling among various configurational degrees of freedom, namely, spin, charge, orbital, and lattice degree of freedom. This coupling can give rise to intriguing long-range phenomena and may result in the emergence of spontaneous electric polarization, magnetic order, and Cooper pair formation among others. Since these effects can occur within the same structural motif, such as in the perovskite structure of complex oxide materials allowing for epitaxial integration, as well as in layered chalcogenide materials that can be easily stacked due to the weak interlayer coupling, the combination of these different and sometimes mutually exclusive phenomena becomes possible at the atomic scale, thus enabling entirely new materials design strategies.
 
In this talk I will give an overview over thin film growth efforts by molecular beam epitaxy at Penn State and highlight, how some of the challenges towards a matured thin film synthesis have been recently overcome, resulting in artificially layered structures with high structural perfection.

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by Dr. Allard Schnabel, Physikalisch-Technische Bundesanstalt (PTB) Berlin

13.02.2020, 17:00 h, TF, Seminar Room C-SR 1

 Abstract

Environments where the magnetic field is far below the earth magnetic field of 50 µT are a prerequisite for many modern precision experiments.  Active magnetic field compensation with coil systems can reduce the external fields by up to two orders of magnitude. Passive magnetic shielding enclosures out of highly permeable material (µr >> 1) can provide volumes of up to 1 m3 with less than 1 nT static magnetic field. In combination with very sensitive magnetic field detectors like SQUIDs and OPMs, numerous basic physics experiments as well as biological studies have been carried out. In the past the driving force for the development of magnetically shielded rooms was brain research due to the spatial and temporal resolution of the neuronal activity. Today the strongest requirements are from basic physics experiments e.g. the search for a finite electric dipole moment of the neutron. These experiments need a homogeneous field of a few µT which should not change by more than 10 fT within 100 s.  

Starting from the basic principles of magnetic shielding, commercially available shields will be discussed before the limits of the strongest existing magnetically shielded rooms, like BMSR-2 at PTB, are presented. In praxis, a larger shielding factor is associated with several restrictions which limit the usage of such shields. The demagnetization process (degaussing), necessary to achieve a low static magnetic field inside the shield, will be discussed in detail. It will also be explained why an “equilibration” of the shielding material is needed to obtain a field stable in time when an additional magnetic field is switched on or used inside the chamber.     

by Prof. Dr. Richard D. James, University of Minnesota

16.01.2020, 13:15 h, TF, Aquarium

Abstract

World population is growing approximately linearly at about 80 million per year.  As time goes by, there is necessarily less space per person.  Perhaps this is why the scientific community seems to be obsessed with folding things. 
We present a mathematical approach to “rigid folding” inspired by the way atomistic structures form naturally.  Their characteristic features in molecular science imply desirable features for macroscopic structures, especially 4D structures that deform.  
Origami structures, in turn, suggest an unusual way to look at the Periodic Table.

 

SFB1261 Microsite

Click here to visit our Microsite with information for students, teachers and the public (German and English version available).

Contact

sfb1261@tf.uni-kiel.de

Chairman:

Prof. Dr. Eckhard Quandt

Kiel University
Institute for Materials Science

 

Internal server

 

CAU

Christian-Albrechts-Universität zu Kiel (CAU)

Christ.-Albrechts-Platz 4
D-24118 Kiel

UKSH

University Hospital Schleswig-Holstein, Campus Kiel (UKSH)

Arnold-Heller-Straße 3
D-24105 Kiel

ISIT

Fraunhofer Institute for Silicon Technology, Itzehoe (ISIT)

Fraunhoferstrasse 1
D-25524 Itzehoe  

IPN

IPN - Leibniz-Institut für die Pädagogik der Naturwissenschaften und Mathematik 

Olshausenstraße 62 
D-24118 Kiel

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