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Imaging currents in two-dimensional quantum materials

date
19.04.2018 
time
02:00 PM - 03:00 PM 
speaker
Prof. Dr. Katja Nowack 
affiliation
Cornell University, Department of Physics, Ithaca, NY, USA 
language
en 
main topic
Physics: general
host
Prof. Dr. C. Felser, Prof. J. Grin, Prof. Dr. A. Mackenzie, Prof. Dr. L. Tjeng 
abstract

Magnetic imaging is uniquely suited to the non-invasive imaging of current densities, particularly in two-dimensional devices. In this talk, I will showcase this approach by discussing measurements on HgTe quantum well devices in the quantum spin Hall (QSH) regime. In a nutshell, we scan a superconducting quantum interference device (SQUID) to obtain maps of the magnetic field produced by the current flowing in a device. From the magnetic image we reconstruct a two-dimensional current distribution with a spatial resolution on the micron scale. This allows us to directly visualize that most of the current is carried by the edges of the quantum well devices when tuned into their insulating gaps - a key feature of the QSH state. I will both discuss routes towards improving the spatial resolution of our measurements to sub-micron length scales through a combination of improved image reconstruction and smaller sensor sizes and outline interesting opportunities for current imaging.

 

Last update: 19.04.2018 07:58.

venue 

Max-Planck-Institut für Physik komplexer Systeme (MPI PKS, Nöthnitzer Straße 38, 01187 Dresden) 
Nöthnitzer Straße 38
01187 Dresden
telefon
+ 49 (0)351 871 0 
e-mail
Max-Planck-Institut für Physik komplexer Systeme 
homepage
http://www.mpipks-dresden.mpg.de 

organizer 

Max-Planck-Institut für Chemische Physik fester Stoffe (MPI-CPfS)
Nöthnitzer Straße 40
01187 Dresden
e-mail
Max-Planck-Institut für Chemische Physik fester Stoffe (MPI-CPfS) 
homepage
http://www.cpfs.mpg.de/ 
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